June 23 - 28 2013 Frauenchiemsee Germany

Mit Unterstützung durch Deutsche Forschungsgemeinschaft und STAIB INSTRUMENTS GmbH

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15th European Symposium on Gas Electron Diffraction Frauenchiemsee, Germany

June 23rd – 28th 2013

PROGRAMME

Sunday June 23

Until 18:00 Arrival / Registration

18:00 Come together / Buffet

Monday June 24 9:00 Norbert Mitzel Bielefeld, GE Opening

Molecular Movies and Clusters Chair: Norbert Mitzel

9:15 Dwayne Miller Hamburg, GE/

Toronto, CA

Making the molecular movie: The chemists’ gedanken-experiment enters the lab frame

10:00 Detlef Schooss Karlsruhe, GE Determination of metal cluster structures by Trapped Ion Electron Diffraction

10:30 Coffee break

Gas Phase Structure

Chair: David Rankin

11:00 Igor Shishkov Moscow, RU The structure of methoxyfurane and noradrenaline as studied by gas electron diffraction and quantum-chemical

calculations

11:30 Georgiy Girichev Ivanovo, RU Combined gas-phase electron diffraction and mass spectrometry: achievements and problems

12:00 End of session

12:15 Lunch

Ultrafast Processes

Chair: Dwayne Miller

13:45 Martin Centurion Lincoln, US Ultrafast electron diffraction from aligned molecules

14:30 Peter Weber Providence, US Electron and X-ray probes of molecular structure on ultrafast time scales

15:00 Dongfang Zhang

Hamburg, GE A femtosecond electron diffraction study: electronically-driven ablation via highly localized electronic states

15:30 Coffee break

Theory and Modeling

Chair: Dines Christen

16:00 Vladimir Tsirelson Moscow, RU Bonding descriptors based on electron density: how does it look now?

16:30 Carole Morrison Edinburgh, UK Exciting ”stuff”: modeling photochemical reactions in the condensed phase. Applications in time-resolved diffraction.

17:00 Michal Kochman Edinburgh, UK The mechanism of solid-state photo-isomerisation reaction

17:30 End of session

18:00 Dinner Scientific Discussions

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Tuesday June 25 Structure in Silicon Chemistry

Chair: Raphael Berger

9:00 David Scheschkewitz Saarbrücken, GE Siliconoids: stable unsaturated molecular silicon clusters

9:45 Ingvar Arnason Reykjavik, IC Properties of monohalogenated silacyclohexanes (CH2)5SiHX; X = F, Cl, Br, I

10:10 Sergey Shlykov Ivanovo, RU Silacyclohexane derivatives

10:35 Coffee break

Structural Features of Selected Compound Classes Chair: Derek Wann

11:00 Attila Kovács Karlsruhe, GE Bond length contraction in actinide compounds

11:25 Peter Pogány Karlsruhe, GE Structural properties of actinide di- and tetracarbides

11:50 Boris Lokshin, Mari-am Ezernitskaya

Moscow, RU Spectroscopic and photochemical studies of substituted cymantrenes

12:20 End of Session

12:30 Lunch

Cultural Excursus Chair: Raphael Berger

13:30 Reinhard Heydenreuter

Penzberg, GE Bavarian history in and around the Chiemsee

14:30 Excursion

Excursion by boat to Herreninsel

19:00 Come together

Reconvening at the Schlosswirtschaft Herrenchiemsee

19:30 Symposium Banquet

(return ca. 23:00)

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Wednesday June 26 Dynamics and Vibration

Chair: Georgii Girichev

9:00 Yuri Tarasov Moscow, RU Intramolecular dynamics and equilibrium structure of non-rigid molecules

9:45 Janne Pesonen Helsinki, FI Vibration and rotation of polyatomic molecules – A geometric algebra approach

10:30 Coffee break

Structural Features of Selected Compound Classes Chair: Nina Giricheva

11:00 Uwe Monkowius Linz, AT Extraordinary temperature dependence of the metal-metal distances in cationic silver(I) complexes bearing

N-heterocyclic carbene ligands

11:30 Jürgen Vogt Ulm, GE New features in the 3D-applet of the forthcoming MOGADOC update

11:50 End of session

12:00 Lunch

13:30 Poster session

Poster Presentations

E. Altova, A. Rykov, L. Khristenko, l. Shishkov

Moscow, RU Molecular structure of α-alanine as studied by gas-phase electron diffraction and quantum chemical calculation

S. Atkinson, S. Masters Christchurch, NZ Development of mass spectroscopy capability with the canterbury gas electron diffraction apparatus

N. Belova, N. Hoang Trang, G. Girichev, H. Oberhammer,

Ivanovo, RU; Tübingen, GE

Tautomeric and conformational properties of acetylacetone, CH3-C(O)-CH2-C(O)-CH3, by gas electron diffraction and

quantum chemical calculations

A.V. Belyakov, Y. Sigo-laev, S. Semenov

St. Petersburg, RU

The silacyclohexanes C5H10SiHCN, C5H10SiH(t-Bu), C5H10Si(t-Bu)CN and C5H10SiHF: a DFT study

A. Bunev, V. Statsyuk, G. Ostapenko

Togliatti, RU Calculating accurate 13

C chemical shifts of azines with density functional methods and modest basis sets

A. Bunev, V. Statsyuk, G. Ostapenko

Togliatti, RU Quantum-chemical investigation of the structure and conformational dynamics amidrazones some azoles

N. Giricheva, N. Belova, M. Fedorov

Ivanovo, RU Heterocyclic aromatic N-Oxides: the nature of semipolar N→O bond and reactive behavior

N. Giricheva, G. Giri-chev, V. Petrov, M. Dak-kouri V. Petrova, S. Ivanov

Ivanovo, RU; Tübingen, Ulm, GE

The structure of 1-naphthalenesulfonyl chloride by gas electron diffraction and quantum chemical calculations

N. Giricheva, V. Petrov, H. Oberhammer, V. Pet-rova, M. Dakkouri, S. Ivanov, G. Girichev

Ivanovo, RU; Tübingen, Ulm, GE

Gas-phase electron diffraction and quantum chemical study of 1-naphthalenesulphonyl fluoride and chloride molecular

structure

N. Giricheva, M. Fedo-rov, S. Ivanov, G. Giri-chev

Ivanovo, RU The electronic and geometric structure of the benzenesulfonic acid methyl ester and its 2- and 4-nitro-substituted molecules

N.Giricheva, M. Fedo-rov, S. Ivanov, G. Giri-chev

Ivanovo, RU Substituent effect on the geometric and electronic structure of benzenesulfonic acid

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Z. Glassman, B. Giro-dias, R. Mawhorter, T. Steimle, M. Jahn, J.-U. Grabow

Claremont, Tempe, USA; Hannover, GE

Electron-nucleus overlap & parity-violating effects in PbF, YbF and RbF

D. Hnyk, D. Wann, H. Robertson, P. Lane, T. Baše, J. Holub

Husinec-Řež, CZ; Edinburgh, GB

Boron-based icosahedra: the structural conse-quences of functionalising the cluster atoms, and their removal

A.A. Ischenko

Moscow, RU Electron diffraction: structure and dynamics of free molecules and condensed matter

I.V. Kochikov, L.S. Khaikin, D.S. Tikhonov, O.E. Grikina

Moscow, RU Analysis of electron diffraction data for 1,3,5-trinitrobenzene molecule with consideration of equivalence of large amplitude

motion coordinates

I. Kolesnikova, O. Doro-feeva, I. Shishkov, I. Hargittai

Moscow, RU; Budapest, HU

Gas-phase electron diffraction and quantum chemical investigation of the molecular structure of benzamide

I. Kolesnikova, O. Do-rofeeva, I. Shishkov, A. Rykov, N. Karasev, H. Oberhammer

Moscow, RU; Tübingen, GE

Molecular structure and conformation of 1,3,5-tris(trifluoro-methyl)-benzene as studied by gas-phase electron diffraction

and quantum chemical calculations

N. Kuze, A. Ishikawa, Y. Ono, H. Takeuchi, S. Konaka

Tokyo, Sapporo, JP

Large-amplitude motions for methyl trifluoroacetate and 2,5-dimethylfuran by GED, MW and quantum chemical

calculation

I. Marochkin, N. Vogt, A. Rykov, O. Dorofeeva, J. Vogt, I. Shishkov

Moscow, RU; Ulm, GE

Molecular structure study of some methyl derivatives of uracil by electron diffraction method and high-level ab initio

calculations

O. Pimenov, G. Giri-chev, V. Maizlish

Ivanovo, RU The structure of free copper (II) 2,9,16,23-tetra-tert-butyl-phthalocyanine: preliminary DFT calculations

A. Pogonin, N. Tverdo-va, A. Ischenko, G. Giri-chev

Ivanovo, Moscow, RU

The molecular structure of zinc(II) etioporphyrin-II: a gas-phase electron diffraction and quantum chemical study

K. Siddiqui, G. Corthey, T. Hasegawa, S. Hayes, K. Pichugin, G. Sciaini, R.J.D. Miller, B. J. Whitaker

Hamburg, GE; Leeds, UK

Ab initio calculations of DNA nucleobases and simulation of electron diffraction patterns

V. Sliznev, N. Belova, G. Girichev, O. Pimenov

Ivanovo, RU Molecular structure of thulium tris-dipivaloyl-methanate, Tm(thd)3, by gas electron diffraction (GED) and DFT

calculations

N. Stepanov Moscow, RU Polyad Quantum Numbers in Vibrational Spectroscopy

V. Tyunina, N. I. Giricheva, G. Girichev

Ivanovo, RU Molecular structure of L-tryptophan

J. Vogt, E. Popov, R. Rudert, N. Vogt

Ulm, GE New features in the 3D-applet of the forthcoming MOGADOC update

N. Vogt, N. Karasev, M. Abaev, A. Makurenkov, W. Leikam, J. Vogt, I. Shishkov

Ulm, Langen-bach, GE; Moscow, RU

Modernization of electron diffractometer EMR-100M

N. Vogt Ulm, GE A benchmark study of molecular structure by GED, MW spectroscopy and coupled-cluster calculations

L.A. Zasurskaya, A.E. Obodovskaya

Moscow, RU Comparative analysis of structures of succinimide and its N-derivatives in crystalline and gaseous phases

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Y. Zhabanov, A. Zak-harov, S. Shlykov, M. Islyaikin, G. Girichev

Ivanovo, RU The structure of a thiadiazole-containing expanded heteroaza-porphyrinoid determined by gas-phase electron

diffraction and DFT calculations.

D. Zhang, S. Bayesteh, H. Delsim-Hashemi, T. Gehrke, F. Mayet, G. Moriena, R.J.D. Miller, et. al.

Hamburg, GE; Toronto, CA

REGAE: Towards Ultrafast electron diffraction and dynamic microscopy

15:30 End of poster session

Instrumentation Chair: Sergey Shlykov

15:30 Sarah Masters Canterbury, NZ A game of two halves: machine development and a conformational conundrum

16:00 Paul Lane Edinburgh, UK Towards megavolt electron diffraction in the UK

16:30 Clemens Schulze-Briese

Baden, CH Hybrid pixel detectors for gas-phase electron diffraction

17:00 Werner Leikam Langenbach, GE Electron-optical equipment for GED

17:30 End of session

18:00 Dinner

19:30 Scientific Discussions

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Thursday June 27 Electrons and electronic effects

Chair: Natalya Belova

9:00 Jan Dillen Stellenbosch, SA Congested molecules: where is the steric repulsion?

9:30 Anna Rita Campa-nelli, Aldo Domeni-cano

L'Aquila, IT

Roma, IT

Transmission of electronic substituent effects through a chain of conjugated double bonds: a quantum chemical study

10:00 Richard Mawhorter Claremont, US Molecules and the electron's electric dipole moment

10:30 Coffee break

Progress in Structural Analysis Chair: Sarah Masters

11:00 Yury Vishnevskiy Bielefeld, GE Development of refinement procedures in gas electron diffraction

11:30 Alexander

Zakharov

Ivanovo, RU Moleculare structure of magnesium octa(m-trifluoromethyl-phenyl) porphyrazine and application of molecular dynamics

for computation of vibrational corrections 12:00 End of session

12:15 Lunch

Associates and Dynamics Chair: Igor Shishkov

14:00 Stuart Young Edinburgh, UK Gas-phase studies of weakly associated species

14:30 Matthew Robinson Edinburgh, UK Pulse dynamics of the Edinburgh time-resolved electron diffractometer

15:00 Konstantyn Pichugin

Hamburg, GE Structural changes in Si induced via auxiliary layer photoexcitation: A femtosecond electron diffraction study

15:30 Coffee break

(Bio-)Organic Structure Chair: Heinz Oberhammer

16:00 Mauricio Alcolea Palafox

Madrid, ES The use of quantum chemical methods in the design of new antivirals

16:30 Christian Reuter Bielefeld, GE Structural results of small chalcogen organyls

17:00 Dines Christen Tübingen, GE Microwave-Microwave-Double-Resonance spectroscopy of acetone in the exited torsional state

17:30 End of session

18:00 Dinner Presentation of the next symposium venue

Friday June 28 8:00-9:30

Breakfast / Departure

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Miller, Dwayne – Monday, 9:15 h

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“Making the Molecular Movie”: The Chemists’ Gedanken Experiment Enters the Lab Frame

R. J. Dwayne Miller Max Planck Group for Atomically Resolved Dynamics,

Department of Physics, University of Hamburg, The Centre for Free Electron Laser Science, DESY and

Departments of Chemistry and Physics University of Toronto

One of the grand challenges in science is to watch atomic motions as they occur during

structural changes. In the fields of chemistry and biology, this prospect provides a direct

observation of the very essence of chemistry and the central unifying concept of transition

states in structural transitions. From a physics perspective, this capability would enable

observation of rarefied states of matter at an atomic level of inspection, with similar

important consequences for understanding nonequilibrium dynamics and collective

phenomena. This experiment has been referred to as "making the molecular movie". Due

to the extraordinary requirements for simultaneous spatial and temporal resolution, it was

thought to be an impossible quest and has been previously discussed in the context of the

purest form of a gedanken experiment. With the recent development of femtosecond

electron pulses with sufficient number density to execute single shot structure

determinations, this experiment has been finally realized (Siwick et al. Science 2003).

Previously thought intractable problems in attaining sufficient brightness and spatial

resolution, with respect to the inherent electron-electron repulsion or space charge

broadening, has been solved. With this new level of acuity in observing structural

dynamics, there have been many surprises and this will be an underlying theme. Several

movies depicting atomic motions during passage through structural transitions relevant to

condensed phase dynamics will be shown (Sciaini et al. Nature, 2009, Ernstorfer et al.

Science 2009, Eichberger et al Nature 2010, Jean-Ruel, J. Phys. Chem. A 2011).

One of the marvels of chemistry and biology is that despite the enormous number of

possible nuclear configurations, chemical processes reduce to a few key modes. The

“magic of chemistry” is this enormous reduction in dimensionality that makes chemical

concepts transferrable. Recent studies using an order of magnitude brighter, rf

compressed, pulses have given the first the first direct atomic view of the barrier crossing

processes and the distillation of chemistry to projections along a few principle reaction

coordinates (Gao et al. Nature 2013). These new developments will be discussed in the

context of developing the necessary technology to study chemical reaction dynamics for

closed quantum systems in the gas phase to open quantum systems with biological

systems representing the extreme limit in system bath couplings affecting reaction

pathways. The overall objective is to directly observe the structure-function correlation in

biomolecules to provide the most fundamental (atomic) basis to rationalize the

evolutionarily optimized topologies of biological systems.

Schooss, Detlef – Monday, 10:00 h

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Determination of metal cluster structures by Trapped Ion Electron

Diffraction

Thomas Rapps1, Eugen Waldt1, Reinhart Ahlrichs2, Manfred M. Kappes1,2, and Detlef

Schooss1,2

1 Karlsruher Institut für Technologie, Institut für Nanotechnologie, Postfach 3640, 76021 Karlsruhe, Germany, and

2 Karlsruher Institut für Technologie, Institut für Physikalische Chemie, Kaiserstrasse 12, 76128 Karlsruhe, Germany

Physical and chemical properties of clusters are directly related to their structure, the

identification of gas phase structures is therefore a central point in cluster science. To

experimentally determine gas phase structures of size selected cluster ions we use the

trapped ion electron diffraction technique (TIED). Structures are assigned by comparison

of experimental and simulated molecular scattering functions, the latter are calculated from

candidate structures obtained from density functional or semi-empirical calculations.

We report electron diffraction measurements on a set of 55 atom homonuclear transition

metal clusters covering essentially all 3d and 4d elements (M55–, M= Sc-Cu, Zr-Mo, Ru-

Ag). At 95 K in gas phase only four different structural families are found: irregular

icosahedral, polytetrahedral, icosahedral and close packed. Elements with the same bulk

structure generally have a common cluster structure type. The four structure types differ in

the maximum coordination number in analogy to the coordination number in the

corresponding bulk lattice. The structures of four prototypical clusters Cu55–, Ti55

– Fe55–

and Ru55– are discussed.

Shishkov, Igor – Monday, 11:00 h

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The structure of methoxyfurane and noradrenaline as studied by gas electron diffraction and quantum-chemical calculations

Prof. Igor F. Shishkov Chemistry Department, M. V. Lomonosov Moscow State University, Moscow, Russia

Recently, in the framework of a joint research carried out with our German colleagues, the Laboratory of electron diffraction investigated the molecule structure of 2-methoxyfurane and noradrenaline using the gas electron diffraction method, as well as quantum-chemical calculations. The quantum-chemical calculations predict the existence of two conformers of 2-methoxyfurane: syn and anti (or quasi-anti). The global minimum corresponds to the syn conformer, whereas the anti form is ~ 1 kcal / mol higher in energy.

Syn Anti

The configuration of the form is flat (Cs). The equilibrium structure of the anti form varies significantly when passing from one method of calculation to a different one. The electron diffraction study made it possible to conclude that in the gas phase both conformers are present, with the likely prevalence of the anti form. The spectroscopic data on the structure of norepinephrine and related compounds containing ethanolamine fragment which are available in the literature, point out to two basic configurations of similar molecules: AG and GG. In this case, although the configuration of pyrocatechol fragment affects the energy of the conformer, it has no appreciable effect on its geometrical structure.

noradrenaline GG AG

Our study of the conformational composition of the vaporous noradrenaline indicates that the GG1 conformers predominate. The observed smaller value of the R-factor for the gauche form gives grounds to conclude that the conformers with gauche orientation of the phenyl and amine groups are present in the mixture. The values of the rh1 geometrical parameters for AG1a and GG1a conformers were determined.

This work was supported by the Russian Foundation for Basic Research (Grant No. 11-03-00716-a and 12-03-91330-NNIO)

Girichev, Georgiy – Monday, 11:30 h

10

Combined gas-phase electron diffraction and mass spectrometry: achievements and problems

Georgiy V. Girichev

Ivanovo State University of Chemistry and Technology, 153000 Ivanovo, Engels av. 7, Russia

The combination of gas-phase electron diffraction (GED) and mass spectrometry(MS)

allows to expand the sphere of using GED from the study of the vapour consisted of only

molecular species to the situations characterised by the complicated vapour composition

and dynamically changing vapour in the scattering volume during experiment

The scheme of the device for an GED/MS experiment is given in the Figure. It allows

- carrying out the set of experiments and using some facilities studying molecular structure

by GED;

- control of the vapour composition and dynamics of vapour pressure during all stages of

experiment including the detection of volatile admixtures;

- overheating the vapour for study of thermal expansion of molecules, for thermal

dissociation of oligomers;

- synthesis of needed species in situ by means of chemical reaction between precursors or

by means of dissociation of suitable solid phase or by thermal decomposition of the

sample.

The main problems concern the uncertainty of vapour composition by MS, which are

connected with:

- using the additive scheme of ionization cross section at interpretation of mass spectra;

- dissociative ionization;

- temperature dependence of mass spectrum is similar to vapour composition change;

- detection of short-living species.

Centurion, Martin – Monday, 13:45 h

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Ultrafast Electron Diffraction from Aligned Molecules

Martin Centurion

University of Nebraska - Lincoln

We have experimentally demonstrated 3D imaging of a symmetric top molecule by using a

femtosecond laser to align the molecules, and a femtosecond electron pulse to capture the

diffraction pattern while the molecules are aligned.1 The 3D structure of the molecule was

retrieved by combining the information from multiple diffraction patterns corresponding to

different projections of the molecule. We are currently working to extend this method to

more complex molecules, and to image structural dynamics on femtosecond time scales.

1 C. J. Hensley, J., M. Centurion, Phys. Rev. Lett. 109, 133202 (2012).

Weber Peter – Monday, 14:30 h

12

Electron and X-ray probes of molecular structure on ultrafast time

scales

Peter M. Weber

Brown University, Providence, Rhode Island, USA, 02806

The ultrafast structural motions of molecules can be observed using diffraction methods or

spectroscopic techniques. The talk reviews the current status of x-ray diffraction

experiments on gaseous samples at SLAC’s LCLS light source. Separately but related,

photoionization – photoelectron spectroscopy out of Rydberg states has been found to be

a superbly capable method to follow structural motions of molecules in real time. The

method is contrasted to diffraction techniques and recent results on several systems are

presented: the isomerization reaction of the quadricyclane/norbornadiene system, and the

charge transfer in dimethylpiperazine. While it is not possible yet to invert the data to

experimentally determine a structure, paths toward making it a structural spectroscopy are

discussed. Interestingly, it is possible to extend the technique into environments at

atmospheric pressures.

Ultrafast time-resolved Rydberg state binding energy spectrum of

dimethylpiperazine showing a very short-lived 3p state (2.2 eV; also inset) and

a long-lived 3s state revealing the signature of charge delocalization dynamics.

Zhang, Dongfang, – Monday, 15:00 h

13

A femtosecond electron diffraction study: Electronically-driven ablation

via highly localized electronic states

Dongfang Zhang1, Masaki Hada1, Julian Hirscht1, Stuart Hayes1, Kostyantyn Pichugin1, Albert Casandruc1, Stephanie Manz1, Regis Y. N. Gengler1, Toshio Seki2, Jiro

Matsuo2,Gustavo Moriena3, German Sciaini1, and R. J. Dwayne Miller1,3

1Max Planck Research Department for Structural Dynamics, Center for Free Electron Laser Science, University of Hamburg, Luruper Chausee 149, 22761 Hamburg, Germany 2Quantum Science and Engineering Center, Kyoto University, Gokasho, Uji, Kyoto 611-

0011, Japan 3Department of Chemistry and Physics, University of Toronto, 80 St. George St., Toronto,

Ontario M5S3H6, Canada

Ultrafast non-thermal melting in semi-metals and semi-conductors has been extensively

studied by femtosecond X-ray and electron diffraction (FED) techniques. The promotion of

valence carriers to the conduction band in such systems is known to lead to highly

delocalized states which, due to their anti-bonding character, provoke to the collapse of

the lattice in the sub-ps timescale. On the other hand, in alkali halides photo excitation

above the band-gap promotes the system to a highly repulsive but rather localized excited

state. This initial state has been known for over a century as the progenitor of lattice

interstitial and vacancy defects involved in the generation of long-lived color-centers1.

Here single-shot time-resolved optical reflectivity and femtosecond electron diffraction

were applied to study the evolution of the ablation process that follows fs-UV-laser

excitation in single crystalline alkali halides. The results reveal fast optical changes

associated with the development of a disordering process and stress that leads to ejection

of neutral fragments and the formation of micron-deep craters. This atypical cold explosion

was found to occur well below the threshold for plasma formation and even the melting

point of the salt. New insights into the very repulsive nature of these highly localized

excited electronic states will be given.

1 K. Tanimura, Phys. Rev. B 2001, 63, 184303

Tsirelson, Vladimir– Monday, 16:00 h

14

Bonding descriptors based on electron density: how does it look now?

Vladimir G. Tsirelson

Mendeleev University of Chemical Technology, Miusskaya Sq., 9, Moscow 125047,

Russia

Concept of bonding, which allows recognizing and classifying the atomic and

molecular interactions, is one of the basic concepts in structural chemistry and solid-state

physics. Semi-classical description of bonding has often led to contradicting mixture of

notions of classical and quantum mechanics, while competitive development of diffraction

and quantum-chemical methods has resulted to a more successive picture of bonding in

molecules and crystals based on the reliable electron density and electrostatic potential.

Correspondingly, new bonding descriptors based on electron density have been

suggested. They allowed to establish which atoms, in terms of electron density, are

chemically bonded and which are not and to quantify the atomic and molecular

interactions. The experimental electron density was also introduced in the DFT formulae: it

allowed extracting the electronic (total, exchange and correlation) energy characteristics

from the X-ray and electron diffraction experiments.

There is a question whether these developments provide new insights into the

nature of atomic and molecular interactions? In search of an answer to this question we

will consider the most recent results dealing with the bonding descriptors based on the

electron density and its derivatives and equally applicable to theoretical and experimental

densities. We will discuss the descriptors which reflect the properties both the atoms and

bonds, all of them are derived by using certain approximations; therefore the limits of their

applicability will be discussed as well.

This work is supported by Russian Foundation for Basic Research, grant 13-03-

00767a.

Morrison, Carole – Monday, 16:30 h

15

Exciting ‘stuff’: modelling photochemical reactions in the condensed

phase. Applications in time-resolved diffraction.

Carole A. Morrison, Michal A. Kochman

School of Chemistry and EaSTCHEM Research School, University of Edinburgh, King’s

Buildings, Edinburgh, EH9 3JJ, UK.

Interpreting the data obtained from time-resolved pump/probe electron diffraction

experiments is challenging, so we have been looking to develop computational modelling

procedures to help with this process. For the solid state, we know that laser-induced

photo-excitation will affect a subset of molecules randomly distributed in the crystal while

the remainder remain in a non-reactive ground state. From a modelling perspective the

problem is therefore how to treat one molecule in a crystal lattice differently to the rest.

We have achieved this aim by adopting a novel implementation of the QM/QM subtractive

paradigm, whereby the reactive molecule is treated using an excited-state quantum

mechanical procedure, such as CASSCF or TD-DFT coupled to a localized basis set,

while the rest of the system is modelled at the DFT level with a delocalized basis set.1 In

this way we can calculate and extract the forces on the atoms. From here we can run

molecular dynamics simulations to model the timescales for photochemical events, or

follow geometry optimisation to obtain a reactive intermediate embedded in a crystal

lattice.

As an illustration of the predictive power of this simulation method, we discuss its

application to the test system of crystalline 7-(2-Pyridyl)-indole.1 We then recount an

investigation into the photocyclization dynamics of 1,2-bis(2,4-dimethyl-5-phenyl-3-

thienyl)perfluorocyclopentene (shown above), where structures generated with the use of

the QM/QM method are compared to electron diffraction data.

1. M. A. Kochman and C. A. Morrison, J. Chem. Theory Comput., 2013, 9, 1182-1192.

Kochman, Michal – Monday, 17:00 h

16

The mechanism of a solid-state photoisomerisation reaction.

Michal A. Kochman, Carole A. Morrison

School of Chemistry and EaSTCHEM Research School, University of Edinburgh, King’s

Buildings, Edinburgh, EH9 3JJ, UK.

Although the solid state may not usually be thought of as an environment suitable for

chemical reactions under mild conditions, several classes of organic compounds in

molecular crystalline form are known to undergo substantial rearrangement under

irradiation with UV light. We discuss the theoretical investigation of one such system,

N-salicylidene-2-chloroaniline,1 by means of the hybrid QM/QM simulation method

introduced in the previous talk.

The cis-enol isomer of this compound exhibits two photoreaction pathways. In the first, the

photoexcited molecule undergoes an intramolecular proton transfer reaction and

subsequently isomerizes to the trans-keto form through a pedal motion, which is to say, a

simultaneous twist around two bonds. The second pathway is non-reactive and leads to

the recovery of the cis-enol isomer. The cis-enol to trans-keto photoisomerisation is

reversible. Following the photoexcitation of a trans-keto molecule, it undergoes a pedal

motion in the same direction as the one involved in the cis-enol to trans-keto

photoisomerisation, leading back to the cis-keto isomer. In the image shown below, the

structure of the system as the trans-keto molecule undergoes the pedal motion is overlaid

on the experimental crystal structure.

1. M. A. Kochman, A. Bil and C. A. Morrison, Phys. Chem. Chem. Phys., in press.

Scheschkewitz, David – Tuesday, 9:00 h

17

Siliconoids: Stable Unsaturated Molecular Silicon Clusters

David Scheschkewitz

Chair for General and Inorganic Chemistry, Saarland University, D-66125 Saarbrücken

The Si=Si bond of disilenes is a suitable molecular model for the most prominent

characteristic of the reconstructed Si(001)-2x1 surface, the ‘buckled dimer’ I.1 This double

bond and similarly surface-protruding features are pivotal to the expansion of silicon

structures, e.g. via surface bonded rings such as II. In addition, nucleation in chemical

vapour deposition techniques is known to proceed via unsaturated species such as

disilenes, small rings, and (partially) substituted silicon clusters.2 The entry to the

preparative modelling of such processes was provided by the disilenide 1 (R = 2,4,6-

iPrC6H2), inter alia allowing for the isolation of a highly chlorinated cyclotrisilane 2.

Reduction of 2 affords 3, an isomer of the still elusive hexasilabenzene, which exhibits a

novel type of aromatic stabilisation that we refer to as dismutational aromaticity.3

The unprecedented structural and electronic features as well as preparative possibilities of

3 will be discussed. This includes access to other stable unsaturated silicon clusters.4 We

recently coined the term “siliconoids” for this novel compound class.5 Finally, the reactivity

of siliconoids with a view to cluster expansion and contraction will be disclosed.

1 Review: J. Yoshinobu, Prog. Surf. Sci. 2004, 77, 37. 2 Example: E. W. Draeger et al., J. Chem. Phys. 2004, 120, 10807. 3 K. Abersfelder, A. J. P. White, H. S. Rzepa, D. Scheschkewitz, Science 2010, 327, 564. 5 K. Abersfelder, A. J. P. White, R. J. F. Berger, H. S. Rzepa, D. Scheschkewitz, Angew. Chem. Int. Ed. 2011, 50, 7936. 6 K. Abersfelder, A. Russell, H. S. Rzepa, A. J. P. White, P. R. Haycock, D. Scheschkewitz, J. Am. Chem. Soc. 2012, 134, 16008.

Arnason, Ingvar – Tuesday, 9:45 h

18

Properties of monohalogenated silacyclohexanes (CH2)5SiHX; X = F, Cl, Br, I

Ingvar Arnason,a Ágúst Kvaran,a Sigridur Jonsdottir,a Sunna Ó. Wallevik,a Katrin L.

Sigurdardottir,a Ragnar Bjornsson,b Alexander V. Belyakov,c Alexander A. Baskakov,c

Thomas Kern,d Karl Hassler,d and Andras Bodie

aScience Institute, University of Iceland, bMax-Planck Institute for Chemical Energy

Conversion, D-45470 Mülheim an der Ruhr, Germany, cSaint-Petersburgh State

Technological Institute, Saint-Petersburgh 190030, Russia, dTechnische Universität Graz,

Stremayergasse 16, A-8010 Graz, Austria, dPaul Scherrer Institute, 5232 Villigen PSI,

Switzerland

The molecular structure of axial and equatorial conformers of cyclo-C5H10SiHX (X = Cl, Br,

and I), as well as the thermodynamic equilibrium between these species was investigated

by means of gas electron diffraction (GED), dynamic nuclear magnetic resonance

(DNMR), temperature-dependent Raman spectroscopy, and quantum chemical calcu-

lations (QC) applying CCSD(T), MP2, and DFT methods. In all cases the axial conformer

is preferred over the equatorial one. When the experimental uncertainties are taken into

account, all experimental and theoretical results for the conformational energy (axial–

equatorial) for the three molecules fit into a remarkable narrow range of –0.50 ± 0.15 kcal

mol–1. The conformational energies for C6H11X and cyclo-C5H10SiHX (X = F, Cl. Br, I, and

At) were compared using CCSD(T) calculations. Preliminary results from Imaging

photoelectron photoion coincidence spectroscopy with velocity focusing electron optics

(IPEPICO) experiments and computer simulations of the dissociative photoionization

process will be introduced.

Shlykov, Sergey – Tuesday, 10:10 h

19

The molecular structure and conformation properties of 1-phenyl-1-

silacyclohexane

Sergey A. Shlykov and Dmitry Yu. Osadchiy

Ivanovo State University of Chemistry and Technology,

Research Institute for Thermodynamics and Kinetics of Chemical Processes,

Engels ave., 7, 153000 Ivanovo, Russia

1-Pheny-1-silacyclohexane was studied by quantum chemical calculations. Four

possible conformers were considered – with orthogonal and coplanar mutual orientations

of phenyl silacyclohexane rings in axial and equatorial positions of the phenyl substituent.

Relative total energies and free Gibbs energies are noticeably different as estimated

by the methods/basis sets applied (Fig. (a) and (b)). The same may be noticed for the

phenyl group rotation barrier (Fig. (c) and (d), dihedral angle Θ is zero at coplanar

orientation of the rings).

Eq_Orthog Eq_Compl Ax_Orthog Ax_Compl

-0.5

0.0

0.5

1.0

1.5

E, k

cal/

mo

l

DFT/6-31G**

DFT/6-311G**

DFT/cc-pVTZ

MP2/6-311G**

CAM-B3LYP/ (cc-pVTZ)

MP2/cc-pVTZ

RT

Conformer

(a)

Eq_ Orthog. Eq_ Compl. Ax_ Orthog. Ax_ Compl.

0.0

0.5

1.0

1.5

2.0

2.5

3.0

G(2

98 K

), k

cal/

mol

Conformer

DFT/6-31G**

DFT/6-311G**

DFT/cc-pVTZ

MP2/6-311G**

CAM-B3LYP/ (cc-pVTZ)

(b)

-150 -100 -50 0 50 100 150

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

E, kca

l/m

ol

, degrees

B3LYP/ (6-311G**)

B3LYP/ (cc-pVTZ)

MP2/ (6-311G**)

MP2/cc-pVTZ

MP2(FULL)/6-311G**

Axial

RT

(c)

-100 -50 0 50 100

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

E, kcal/

mol

, degrees

B3LYP/6-311G**

B3LYP/cc-pVTZ

MP2/6-31G**

MP2/6-311G**

MP2(FULL)/6-311G**

Equatorial

(d)

Kovács, Attila – Tuesday, 11:00 h

20

Bond length contraction in actinide compounds

Attila Kovács, Peter Pogány, Rudy J. M. Konings

European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O.

Box 2340, 76125 Karlsruhe, Germany

One of the most important structural features of f-elements is the systematic contraction of

their neutral and ionic radii along the lanthanide/actinide row of the periodic system1 due to

the poor shielding of nuclear charge by f electrons. This results in the valence s (6s and 7s

in lanthanides and actinides, respectively) electrons drawn towards the nucleus, thus

leading to smaller atomic and ionic radii.

The contraction can be expected in the compounds of f-elements with strong ionic

character, where the bond lengths are determined by the ionic radii. In compounds with

considerable covalent character the bond lengths are influenced by the molecular orbital

interactions, too.

Recently we performed systematic theoretical studies on several groups of actinide

molecules: AnO, AnO2 (An = Th–Lr),2 AnC2 (An = Th, U, Pu, Am)3 and AnCl3 (An = Th–

Cm). In our presentation the characteristic geometrical features found in the four series will

be shown. The variation of the bond lengths along the actinide row are explained on the

basis of the ionic vs covalent characters and molecular orbital interactions.

1 N. M. Edelstein, J. Fuger, J. J. Katz, L. R. Morss, Summary and Comparison of Properties of the Actinide and Transactinide Elements. In The Chemistry of the Actinide and Transactinide Elements, N. M. Edelstein, J. Fuger, L. R. Morss, Eds. Springer: Dordrecht, 2006; Vol. 3, pp 1753–1835. 2 A. Kovács, P. Pogány, R. J. M. Konings, Inorg. Chem. 2012, 51, 4841–4849. 3 P. Pogány, A. Kovács, D. Szieberth, R. J. M. Konings, Struct. Chem. 2012, 23, 1281–1289.

Pogány, Peter – Tuesday, 11:25 h

21

Structural properties of actinide di- and tetracarbides

Peter Pogánya, Attila Kovácsa,b,Rudy J. M. Koningsa

aEuropean Commission, Joint Research Centre, Institute for Transuranium Elements,

P.O.Box 2340, 76125 Karlsruhe, Germany

bDepartment of Inorganic and Analytical Chemistry, Budapest University of Technology

and Economics, Szent Gellért tér 4., H-1111 Budapest, Hungary

DFT (B3LYP) and CASPT2 calculations were performed on actinide (Th, U, Pu, Am) di-

and tetracarbides. We performed a thorough search for the possible structural isomers of

these compounds, and determined their energetic, bonding and spectroscopic properties.

Five different structures were investigated for AnC2 and twelve structures for AnC4. The

most stable structures have symmetric triangular (1) and fan-like (2) character for di- and

tetracarbides, respectively.

(1) (2) (3) (4)

Some higher energy structures were also studied, since some linear dicarbides (4) were

found in Ar and Ne matrix isolation experiments, whereas the thermodynamically more

stable triangular structure (1) was not found. In case of ThC2 and ThC4 the DFT methods

predicted geometries significantly different what was found with CASPT2, however after

performing wavefunction stability investigations the ground state was identified. The

biggest difference was observed in case of ThC2, where DFT and some single referent HF

and post-HF methods gave asymmetric triangular structure (3) as minimum. After

changing the electronic configuration symmetric triangular (2) structure was found with

most of other methods. The IR frequencies of the investigated structures were also

determined.

P. Pogány, A.Kovács, Z. Varga, F. M. Bickelhaupt, R. J. M. Konings, J. Phys. Chem.,

2012, 116, 747–755.

P. Pogány, A. Kovács, D. Szieberth, R. J. M. Konings, Struct. Chem., 2012, 23, 1281–

1289.

Lokshin, Boris + Ezernnitskaya, Mariam – Tuesday, 11:50 h

22

Spectroscopic and photochemical studies of substituted cymantrenes

Mariam Ezernitskaya, Boris Lokshin, Elena Kelbysheva, Tatyana Strelkova, Yurii Borisov,

and Nikolay Loim

A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences

28 Vavilova str. 119991 Moscow, Russian Federation

We report photochemical properties and photochromism of monosubstituted derivatives of

cymantrene containing in the substituent n-donating (carbamate, amide, pyridine) and -

donating (allyl, propargyl) groups capable of forming intramolecular chelates with the

manganese atom in the 16e intermediate formed upon irradiation. In the course of

irradiation the color of solution changed to crimson. In the dark reaction in the presence of

CO the color restored and the parent compound was formed. The structure and properties

of these chelates were elucidated from UV-vis, IR, NMR spectra and confirmed by DFT

calculations. For compounds containing in the substituent amide groups, stable

photochromic systems were obtained in a high quantum yield and fast dark response,

which could stand many cycles without decomposition. In the case of compounds

containing two functional groups (for example, pyridine and allyl), two chelates were

simultaneously formed upon irradiation, and dark reaction was slow and occurred at the

expense of intramolecular linkage isomerisation even in the absence of CO. The influence

of the nature of the donor group and its position in the substituent on the thermodynamic

stability of the chelates formed and their photochemical behaviour is discussed.

Heydenreuter, Reinhart – Tuesday, 13.30 h

23

Prof. Dr. Reinhart Heydenreuter

„Bavarian history

in and around

Chiemsee“

Tarasov, Yury – Wednesday, 9:00 h

24

Intramolecular dynamics and equilibrium structure of non-rigid

molecules: 2-Nitroethanol.

Dmitry Kovtun, Igor Kochikov, Arkady Ivanov, Yury Tarasov

M.V. Lomonosov Moscow State University, 119991, Moscow, Russia

M.V. Lomonosov Moscow State University of Fine Chemical Technologies, 119571,

Moscow, Russia

2-Nitroethanol molecule has been studied earlier by spectroscopic and QC methods1-3.

Conformation but not structural parameters of this molecule were determined

experimentally.

In our study results of combined analysis of GED intensities, vibrational frequencies1 and

rotational constants2 accompanied with QC calculations are reported based on the

treatment given in 4.

The most stable rotamer with hydrogen bonding

is shown in the Figure. The final structural results

are presented in the Table. Values in parentheses are 3σ, upper indexes denote

parameters optimized in groups. The barrier height was evaluated as 500±300 cm-1.

1 P.A. Giguère, T. Kawamura, Can. J. Chem. 1971, 49, 3815. 2 K. M. Marstokk, H Møllendal, Acta Chem. Scand. 1996, 50, 505.

3 T. Varnali, I. Hargittai, J. Mol. Struct. (Theochem), 1996, 388, 315.

4 I. V. Kochikov, Yu. I. Tarasov, N. Vogt, V. P. Spiridonov, J. Mol. Struct. 2002, 607, 163.

MP2/cc-

pVTZ

GED+IR+

MW+QC

re(С-N), Å 1.496 1.500(3) a

re(C-C), Å 1.511 1.515(3) a

re(C-O), Å 1.410 1.414(3) a

re(N-O3), Å 1.232 1.231(2) b

re(N-O4), Å 1.225 1.224(2) b

e ONO, ° 125.2 125.2(0.3)

e NCC, ° 112.3 111.8(0.7)

e CCO10, ° 112.9 112.5(0.7)

Pesonen, Janne – Wednesday, 9:45 h

25

Vibration and rotation of polyatomic molecule – A geometric algebra

approach

Janne Pesonen

Department of Chemistry, University of Helsinki, P.O. BOX 55, FIN-00014 Helsinki,

Finland

In order to model the vibration-rotation spectra of polyatomic molecules, and the

corresponding wave functions in spectroscopic accuracy, one needs to set up the

molecular Hamiltonian as exactly and yet as intuitively as possible. In practice, this means

using some geometrically defined internal coordinates (such as bond lengths, bond angles

and torsion angles), and using an explicitly defined body-frame, in contrast to the old

approach of using normal coordinates and Eckart frame. The (theoretically) most difficult

problem is to obtain the proper representation of the kinetic energy operator, especially its

Coriolis part. These difficulties are easily overcome by the recently developed geometric

(Clifford) algebra approach to kinetic energy operators1. Unfortunately, this methodology is

still not as widely known as it should be.

1 J. Pesonen, L. Halonen, Recent advances in the theory of vibration-rotation

Hamiltonians. Adv. Chem. Phys. 2003, 125, 269–348.

Monkowius, Uwe – Wednesday, 11:.00 h

26

Extraordinary temperature dependence of the metal-metal distances in

cationic silver(I) complexes bearing N-heterocyclic carbene ligands

Margit Kriechbaum,a Johanna Hölbling,a Christa Hirtenlehner,a Georg Stammler,b

Raphael J. F. Berger,*c and Uwe Monkowius*a

aInstitut für Anorganische Chemie, Johannes Kepler Universität Linz, Altenbergerstr. 69, 4040 Linz, Austria; E-mail: uwe.monkowius@jku.at; bLehrstuhl für Anorganische Chemie und Strukturchemie, Universität Bielefeld, Universitätsstr. 15, 33615 Bielefeld, Germany cMaterialwissenschaften und Physik, Abteilung Materialchemie, Paris-Lodron Universität Salzburg, Hellabrunner Str. 34, 5020 Salzburg, Austria; E-mail: raphael.berger@sbg.ac.at

Metallophilic closed-shell interactions are an established concept in coordination chemistry

of coinage metals with formal electronic nd10 configurations. They are most prominent for

linear two-coordinate Au(I) compounds with binding energies of the order of hydrogen

bonds, and less pronounced for the lighter congeners Ag(I) and Cu(I).

In this contribution, we will present a strong temperature dependence of the Ag–Ag

distances in Ag(I) complexes bearing N-heterocyclic carbenes (NHCs). NHC-Ag(I)

complexes are versatile NHC transfer agents and a plethora of compounds has been

reported. Complexes of the form [(NHC)2Ag]A (A = non-coordinating anion) are formed by

the reaction of Ag2O and the respective imidazolium salt. In the case of small substituent

on the NHC-ligand, complexes with Ag–Ag con-

tacts are formed. For the iso-propyl substituted

NHC ligand, the complex [(NHC)2Ag]PF6 features

an alteration of the Ag–Ag bond length of up to 10

% in the temperature range of 100–293 K, which is

more than the “colossal thermal expansion” of the

Prussian Blue analogue Ag3[Co(CN)6].1 We ascribe

this behaviour to a highly anharmonic, flat potential

of argentophilic interactions and proved this hypo-

thesis by means of quantum-chemical interaction

on a suitable model system.

1 A. L. Goodwin et al. Science 2008, 319, 794.

Vogt, Jürgen – Wednesday, 11:30 h

27

New features in the 3D-applet of the forthcoming MOGADOC update

J. Vogt, E. Popov, R. Rudert, and N. Vogt

Chemical Information Systems, University of Ulm, 89069 Ulm, Germany

The MOGADOC database (Molecular Gas-Phase Documentation) has been grown up to

11,500 inorganic, organic, and organometallic compounds, which were studied by in the

gas-phase by microwave spectroscopy, radio astronomy and electron diffraction. The

database contains about 9,000 numerical datasets with internuclear distances, bond an-

gles and dihedral angles. Most of the corresponding molecular structures are also given as

3D presentation (ball-stick-models). The retrieval features of the HTML-based database

have been described elsewhere in details. Some years ago a Java-based applet has been

developed, which enables the 3D-visualization of the molecular structures. The user can

interactively rotate, shift and scale the 3D-models, can “measure” bond lengths as well as

bond, dihedral and elevation angles1.

Recently new “measurement” features have been supplemented (such as for distances

between centroids, angles between ring planes etc.).

The project has been supported by the Dr. Barbara Mez-Starck Foundation, Freiburg

1 N. Vogt, E. Popov, R. Rudert, R. Kramer, and J. Vogt, J. Mol. Struct. 2010, 978, 201

Masters, Sarah – Wednesday, 15:30 h

28

A Game of Two Halves: Machine Development and a

Conformational Conundrum

Christopher O. Burn, Sandra J. Atkinson and Sarah L. Masters

Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch 8140,

New Zealand, sarah.masters@canterbury.ac.nz

This talk will be presented in two parts. The first part will deal with the development of

mass spectrometric capability with the Canterbury gas electron diffraction (GED)

apparatus, the options available to us, and progress thus far. We will also discuss the

planned technical upgrades for the apparatus. The second part will deal with the

conformational conundrum presented by a sterically loaded phosphine. The steric loading

and subsequent effect on geometry of phosphines is of interest to both structural chemists

and synthetic chemists who use these ligands in preparative methods. The gaseous

molecular structures of various sterically loaded phosphines have been investigated,

including bis(trichlorosilyl)tert-butylphosphine,1 bis(tert-butyl)trichlorosilylphosphine2 and

tri(tert-butyl)phosphine.3 In current work the gaseous molecular structure of isopropyl-tert-

butyl-trichlorosilylphosphine (PButPriSiCl3) has been investigated experimentally using

GED and computationally using ab initio and density functional theory (DFT) methods.

Several conformers were predicted for the structure via computational methods. Whilst all

methods predicted the existence of six conformers on the potential energy surface, there

was a lack of agreement between methods on the energy ordering of these conformers.

Can we use the experimental data to guide us when deciphering the energy ordering of

these conformers, or will the conformational conundrum of this asymmetric phosphine

remain unsolved?

1 S. L. Hinchley, H. E. Robertson, D. W. H. Rankin,W.-W. du Mont, J. Chem. Soc., Dalton Trans. 2002, 3787. 2 W.-W. du Mont, L. Müller, R. Martens, P. M. Papathomas, B. A. Smart, H. E. Robertson and D. W. H. Rankin, Eur. J. Inorg. Chem. 1999, 1381. 3 H. Oberhammer, R. Schmutzler and O. Stelzer, Inorg. Chem. 1978, 17(5), 1254.

Lane, Paul – Wednesday, 16:00 h

29

Towards megavolt electron diffraction in the UK

Paul D. Lane, Adam Kirrander and Derek A. Wann

School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh, UK EH9 3JJ

Julian W. McKenzie, Mark Surman, Jim Clark and David M. P. Holland

STFC Daresbury Laboratory, Warrington, UK WA4 4AD

We are in the process of developing megavolt electron diffraction in the UK using the 5

MeV electron source VELA (formerly the electron beam test facility) at Daresbury

laboratory. Such facilities exist elsewhere in the world,1,2 but are not currently available in

the UK. This facility would allow electron diffraction studies to be performed with sub-100-

fs electron pulses3 as, by employing relativistic electrons, the space-charge broadening

that is problematic for table-top experiments becomes negligible. Also, the high number of

electrons per pulse could make single-shot time-resolved experiments possible. This

combination would allow the observation of structural changes on the timescales that are

important for chemical processes.

In this work we look at the key electron beam characteristics and experimental geometries,

and simulate a complete experiment to determine the quality of diffraction data that could

be expected from the facility.

1 J. B. Hastings, F. M. Rudakov, D. H. Dowell, J. F. Schmerge, J. D. Cardoza, J. M.

Castro, S. M. Gierman, H. Loos and P. Weber, Appl. Phys. Lett. 89, 184109 (2006).

2 P. Musumeci, J. T. Moody and C. M. Scoby, Ultramicroscopy 108, 1450 (2008).

3 J. W. McKenzie, D. Angal-Kalinin, J. K. Jones and B. L. Militsyn, Proceedings of

IPA2012, 1560 (2012).

Schulze-Briese, Clemens – Wednesday, 16:30 h

30

Hybrid pixel detectors for gas phase electron diffraction

Clemens Schulze-Briese on behalf of DECTRIS

DECTRIS Ltd., Neuenhoferstrasse 107, 5400 Baden, Switzerland

Hybrid pixel detectors have the potential to transform the detection of electrons in a similar

manner as they have transformed synchrotron research by enabling new data acquisition

modes and even novel experiments. During the last years prototype experiments have

been carried out to demonstrate their potential in electron microscopy [1], electron

diffraction [2] as well as low energy electron detection [3].

PILATUS [4] hybrid pixel detectors, first introduced in 2007, have completely changed the

way X-rays are detected. Data quality has improved due to the noise-free operation and

the direct conversion of the X-rays, while millisecond readout time and high-frame rates

allow for hitherto unknown data acquisition speed and efficiency.

The modular architecture and the vacuum-compatibility of the detector modules are ideal

prerequisites to design specific detector solutions with properties well beyond those of the

standard models. In-vacuum operation is ideally suited to eliminate all background arising

from windows and air, resulting in optimal signal-to-noise ratio. Furthermore, the lowest

experimental energy is no longer limited by windows and air absorption but rather by the

beamline spectrum and the detector. The minimal X-ray energy compatible with noise-free

counting for the PILATUS is below 2 keV.

Here we present the prospects of using PILATUS and EIGER [5] detectors in gas phase

electron diffraction experiments. In particular the EIGER detector with its pixel size of 75

µm and module dimensions of 1024 by 512 pixels seems to be well adapted to the

experimental requirements. The detector features continuous readout with a dead time of

only 3 µs. For a detector consisting of 8 modules with an area of approximately 16 by 15

cm2 frame rates of up to 750 Hz can be achieved. The count rate per pixel can be as high

as 2·106 electrons/second.

1 G. McMullan et al., Ultramicroscopy. 2009, 109, 1126 2 D. Georgieva, et al., JINST 2011 6 C01033 3 R. van Gastel et al., Ultramicroscopy. 2009, 109, 111 4 P. Kraft, et al., J. Synchrotron Rad. 2009, 16, 368 5 R. Dinapoli et al., NIM A. 2011, 650(1), 79

Leikam, Werner – Wednesday, 17:00 h

31

Electron-optical equipment for GED

Werner Leikam

Staib Instruments GmbH, D-85416 Langenbach Hagenaustr. 22

In recent years Staib Instruments has delivered electron-sources to replace the original

source of the Balzers Eldigraph KD-G21,2. On this basis an advanced electron optical

column for GED will be presented. The column is intended for routine GED-analysis. The

adjustment of the column is achieved only by electronic means. Disturbances which

reduce the resolution of the GED will be discussed.

1 W. Zeil, J. Haase, L. Wegmann, Z. Instr.1966, 74, 84 2 R. J. F. Berger, M. Hoffmann, S. A. Hayes, N. W. Mitzel, Z. Naturforsch. 2009, 64b, 1259

Dillen, Jan - Thursday, 9:00 h

32

Congested Molecules – Where is the Steric Repulsion?

Jan Dillen

Department of Chemistry and Polymer Science, Stellenbosch University

Private Bag X1, Matieland 7602, South Africa

The computed electron density of several congested saturated hydrocarbons and

halogenated derivatives has been analysed by the method of Interacting Quantum Atoms

(IQA).1 For all the molecules studied, the calculations show the existence of a bond path

between the congested atoms and which, according to the Quantum Theory of Atoms in

Molecules (QTAIM),2 indicates that there is a stabilising interaction between these atoms.

The bond path is found to exist up to inter-atomic distances well beyond the sum of the

Van der Waals radii.

The IQA results indicate that steric hindrance is not a repulsive force between the

congested atoms, but that is the result of an increase in the intra-atomic or self-energy of

the congested atoms. This increase in self-energy is caused by the deformation of the

atomic basin of the congested atoms.

Molecular graph, critical points, and atomic volume of one of the congested hydrogen

atoms in tetracyclododecane as a function of the HH distance.

In all the molecules, and within the range of molecular deformations used in this study, the

increase in self-energy of the atoms has no influence on the presence of a bond path

between the congested atoms. Neither has the fact whether the pair wise interaction

between the congested atoms as calculated with IQA is attractive or repulsive, an

influence on the existence of that bond path.

Based on the results of this study, one has to conclude that neither bond paths, nor

individual pair wise interaction energies as calculated with the IQA formalism, are useful

indicators for the existence or absence of steric hindrance.

1 M.A. Blanco, A.M. Pendás, E. Francisco, J. Chem. Theory Comput. 2005, 1, 1096–1109

2 R.F.W. Bader, Atoms in Molecules: A Quantum Theory, 1990, Oxford, University Press

Campanelli, Anna Rita + Domenicano, Aldo, - Thursday, 9:30 h

33

Transmission of electronic substituent effects through a chain of

conjugated double bonds: a quantum chemical study

Anna Rita Campanellia and Aldo Domenicanob

a Department of Chemistry, Sapienza University of Rome, 00185 Rome, Italy b Department of Physical and Chemical Sciences, University of L’Aquila, 67100 L’Aquila,

Italy

The transmission of electronic substituent effects through a chain of conjugated

double bonds has been investigated by analysing the structural variation of a phenyl

probe induced by a variable substituent X in four series of molecules, Ph(CH=CH)nX

with n = 14. For each series the structures of 46 molecules have been determined by

MO calculations at the B3LYP/6-311++G** level of theory, imposing all-trans

conformation and Cs symmetry.

As in our previous studies of other hydrocarbon frameworks,1 the structural

variation of the phenyl probe is represented by a linear combination of the internal ring

angles, termed SF. Multiple regression analysis of SF values using suitable indicators of

electronic substituent effects shows that the structural variation of the phenyl probe is

determined primarily by the following effects (listed in order of decreasing importance):

(i) the field effect, enhanced by field-induced -polarization of the polyenic chain, (ii) a

resonance-induced field effect, caused by the resonance -charges on the C atoms of

the chain, and (iii) the electronegativity effect, which decreases rapidly with distance (it

disappears when n > 2). The relative importance of field versus resonance effects

increases gradually as the chain becomes longer. Direct -electron transfer from the

benzene ring to the chain, or vice versa, due to resonance effects and field-induced -

polarization, is shown to give rise to quadratic terms in the regression.

The SF parameters are closely related to the electron density distribution in the -

system of the molecules. They are well reproduced by a linear combination of the -

charge residing on the C atom of the chain and the absolute value of the -charge

transferred from the benzene ring to the chain, or vice versa.

References

1. A. R. Campanelli, A. Domenicano, Struct. Chem. 2013, 24, DOI 10.1007/s11224-013-0242-0; A. R. Campanelli, Struct. Chem. 2013, 24, DOI 10.1007/s11224-013-0231-3; and references therein.

Mawhorter, Richard – Thursday, 10:00 h

34

Molecules and the electron's electric dipole moment

Richard Mawhorter1, Zachary Glassman1, Benjamin Girodias1,

Trevor Sears2, Chris McRaven2, Lukas Alphei3, & Jens-Uwe Grabow3

1Physics Dept., Pomona College, Claremont, CA 91711 USA

2Chemistry Dept., Brookhaven National Laboratory, Upton, NY 11973 USA

3Institut für Physikalische Chemie, Leibniz-Universität, Hannover D 30167

Polar diatomic molecules

are ideal laboratories for

investigating the effects of

parity non-conservation, and

high resolution microwave

spectroscopy provides a unique

window onto these tiny effects.

These include the nuclear

anapole moment and the

electric dipole moment of the

electron, or eEDM.

Motivated by the ongoing

search for the eEDM and the

opportunity to confirm the lone anapole moment measurement in atomic cesium, rotational

spectra of all 4 isotopologues of the PbF radical (see energy level diagram by Neil Shafer-

Ray) were measured using a supersonic jet Fourier transform microwave spectrometer at

the Leibniz Universität in Hannover. Field-free and Zeeman measurements over a range of

3 - 26 GHz have resulted in the discovery of the near-degeneracy of 2 states of opposite

parity in 207PbF and the determination of 2 new spectroscopic parameters. They further

provide a confirmation of the relative insensitivity of PbF to stray magnetic fields in an

eEDM experiment, as well as a stringent test of the quality of calculated PbF wave

functions. New work on YbF as well as a means to extend the reach of microwave

spectroscopy even further towards the mHz regime of the eEDM will also be presented.

Vishnevskiy, Yuri – Thursday, 11:00 h

35

Development of refinement procedures in gas electron diffraction

Yury V. Vishnevskiy and Norbert W. Mitzel

Bielefeld University, Universitätsstraße 25, Bielefeld, Germany

Traditional procedures for refinement of the molecular structure in the GED method require

definition of molecular geometry in terms of independent internal coordinates. In the stable

version of the UNEX1 program this is done by defining z-matrices for molecules. However,

this approach limits accuracy of refined molecular parameters and hinders automation of

structural analysis. Introduction of the method of predicate observations2 has played an

important role in the development of the GED method and lead to elaboration of the

SARACEN method,3 in which flexible restraints are used instead of fixed constraints.

Nevertheless, this approach still uses independent internal coordinates (bond lengths,

angles, etc.) as parameters to be refined. This, in turn, leads to ambiguity in choosing of

such sets of coordinates and, as a consequence, to a decrease of the real accuracy of

refined the molecular structure. To overcome this problem we have recently developed a

procedure for refinement of molecular geometry in terms of Cartesian coordinates with

additional usage of theoretical data for regularization purposes.4 The first molecule refined

both with new and conventional procedures was 3-methyl-1-boraadamantane. Detailed

analysis of errors of refined parameters proved that the new method outperforms the

traditional one. Our current activity includes the further development of the described

refinement procedure in order to increase accuracy and automation of the GED method in

general.

1 Yu. V. Vishnevskiy, http://unexprog.org

2 L. S. Bartell, D. J. Romenesko, T. C. Wong, Molecular Structure by Diffraction Methods,

The Chemical Society, London, 1975, 3, 72 – 79.

3 N. W. Mitzel, D. W. H. Rankin, Dalton Trans., 2003, 3650 – 3662.

4 Yu. V. Vishnevskiy, M. A. Abaev, A. N. Rykov, M. E. Gurskii, P. A. Belyakov, S. Yu.

Erdyakov, Yu. N. Bubnov, N. W. Mitzel, Chem. Eur. J., 2012, 18, 10585 – 10594.

Zakharov, Alexander – Thursday, 11:30 h

36

Molecular structure of magnesium octakis(m-trifluoromethylphenyl)

porphyrazine and application of molecular dynamics for computation of

vibrational corrections

Alexander Zakharov, Yuriy Zhabanov, Sergei Shlykov and Georgiy Girichev

Ivanovo State University of Chemistry and Technology, Research Institute of Chemistry of Macroheterocyclic Compounds, F. Engels av. 7, Ivanovo 153000, Russian Federation

The gas-phase molecular structure of the magnesium octa(m-trifluoromethylphenyl)

porphyrazine (MgC72H32N8F24) has been studied by a synchronous gas-phase electron

diffraction (GED) and mass

spectrometric experiment and

density functional theory

calculations using the B3LYP

hybrid method and triple-ζ

valence basis sets. The mole-

cule has an equilibrium

structure of D4 symmetry with

almost planar macrocycle (see

the figure). In this study we

applied a method of calcula-

ting vibrational corrections

using molecular dynamics

(MD) simulations, which has

been recently reported.1, 2

This technique has an advan-

tage of directly producing corrections to equilibrium distances, allowing to determine

equilibrium structures from GED data. In the present study we successfully used DFT MD

with the level of theory similar to one utilised in force field computations.

The study was supported by the RFBR, grant no. 13-03-00975. 1 D. A. Wann, R. J. Less, F. Rataboul, P. D. McCaffrey, A. M. Reilly, H. E. Robertson, P. D. Lickiss, D. W. H. Rankin, Organometallics 2008, 27, 4183. 2 D. A. Wann, A. V. Zakharov, A. M. Reilly, P. D. McCaffrey, D. W. H. Rankin, J. Phys. Chem. A 2009, 113, 9511.

Young, Stuart – Thursday, 14:00 h

37

Gas-phase electron diffraction of weakly associated species

Stuart Young, Matthew Robinson, Paul Lane and Derek Wann

University of Edinburgh, Joseph Black Building, West Mains Road, EH9 3JJ

Weakly associated species, such as strong van der Waals interactions, cannot be

efficiently studied using conventional effusive nozzles. Apparatus in Edinburgh has been

adapted to use a supersonic expansion nozzle assembly to vibrationally cool samples,

allowing structural determination of dimers and complementary molecules. Other novel

features of the apparatus include a telefocus gun capable of producing a high intensity

electron beam, needed to view small sample density, and a CCD camera.

Counterpoise calculations have been carried out for pyrazole, pyridine-2-ol, silyl chloride

and silyl iodide dimers as well as complementary pseudo base-pairs. Utilising frequency

calculations, radial distribution curves were simulated at 100 K, showing increased detail

at larger interatomic distances, which would be related to the weak interactions.

Robinson, Matthew – Thursday, 14:30 h

38

Pulse dynamics of the Edinburgh time-resolved electron diffractometer

Matthew S. Robinson, Stuart Young, Paul D. Lane, Derek A. Wann

School of Chemistry, The University of Edinburgh, Joseph Black Building, King’s Buildings,

Edinburgh, EH9 3JJ

We have assembled and tested our new compact time-resolved gas electron

diffractometer. In this talk I will discuss the properties of the diffractometer, and its potential

capabilities, before going on to detail the types of simulations that we have carried out to

determine the properties of the apparatus. We will look at the time-resolution of the

apparatus as a whole, as well as other beam properties at the various points throughout

the electrons’ flight, and how these are affected by the introduction of a magnetic lens to

the apparatus. Comparisons on the efficiency of different particle tracer programs will also

be discussed, including SIMION1 and General Particle Tracer2.

1. D. A. Dahl, SIMION for the personal computer in reflection. Int. J. Mass Spectrom., 200:3-25, 2000.

2. S. B. Van Der Geer and M. J. De Loos, General particle tracer. Elements, 1–202, 2009

Pichugin, Kostyantyn – Thursday, 15:00 h

39

Structural changes in Si induced via auxiliary layer photoexcitation:

A femtosecond electron diffraction study

Kostyantyn Pichugin1, Hayes Stuart1, Shelley A. Scott3, Max G. Lagally3, Dongfang Zhang1, Julian Hirscht1, Albert Casandruc1, Masaki Hada1, Germán Sciaini1, and R. J.

Dwayne Miller1;2;*

1 Max Planck Institute for Structure and Dynamics of Matter, Department of Physics,

University of Hamburg, Center for Free Electron Laser Science, DESY, D-22607, Hamburg, Germany.

2 Departments of Chemistry and Physics, University of Toronto, Toronto, Ontario, M5S 3H6, Canada.

3 University of Wisconsin-Madison, Madison, WI 53706, USA * dwayne.miller@mpsd.cfel.de

Ultrafast electron diffraction (UED) is an indispensable tool capable of tracking minute

changes in materials structure on the femtosecond timescale. However, in practice time-

resolved studies are often limited to the materials which can be photoexcited within the

range of wavelengths readily available from commercial lasers. Recently, Hada et al. [1]

demonstrated a semiconductor-to-metal phase transition in VO2 driven by hot electrons

photoinjected from an adjacent Au nano-layer. The idea of using non-transparent media as

a secondary source of excited carriers to trigger structural changes in the target material is

of great importance because it offers a general approach to soften the aforementioned

restriction.

In this work we extend the auxiliary excitation source concept to UED experiments. For the

model sample we have chosen a nanocomposite comprised of a 20 nm Al layer deposited

on top of a 49 nm single crystalline Si membrane. Consequently, when the sample is

illuminated with the fundamental of Ti:Sapphire laser the aluminum layer becomes the

major supplier of excited carriers since the silicon material is largely transparent at 800 nm

wavelength. All measurements were conducted with a newly built electron diffraction appa-

ratus that provides sub-picosecond electron bunches at 1 kHz repetition rate. Our prelimi-

nary results for the time dependent series of diffraction patterns reveal several oscillations

with a period of 11 ps corresponding to the longitudinal acoustic wave propagating in Si

film along the surface normal. These findings are in a good agreement with the previous

UED studies which involved direct UV photo-doping in free-standing silicon films [2].

1 M. Hada, D. Zhang, A. Casandruc, and R. J. D. Miller, Phys. Rev. B., 86, 134101, 2012. 2 M. Harb, W. Peng, G. Sciaini, C. T. Hebeisen, R. Ernstorfer, M. A. Eriksson, M. G. Lagally, S. G. Kruglik, and R. J. D. Miller, Phys. Rev. B., 79, 094301, 2009.

Palafox, Mauricio Alcolea - Thursday, 16:00 h

40

The use of quantum chemical methods in the design of new antivirals

M. Alcolea Palafox, and N. Iza

Departamento de Química-Física I, Facultad de Ciencias Químicas

Universidad Complutense, Ciudad Universitaria, Madrid-28040, Spain

The first phosphorylation of the nucleosides analogues by the ATP kinase is a crucial step

in the activity of the prodrugs. The proportion of compound phosphorylated is in general

very small in the mayority of the prodrugs. Thus, for the design of new effective antivirals it

is important to understand this first phosphorilation step. Efficient phosphorylation depends

largely on the spatial structure of the nucleoside. Thus, an extensive conformational

analysis identifying all minima on the potential energy surface can be considered as a first

step. Among the prodrugs, those derivatives of deoxythymidine (R1=CH3, R2=OH, R3=H)

were the most used, Fig. 1. Structures with a hydrophilic group in R2 facilitate opened

clusters with a long O2···O5 distance and easier phosphorylation, i.e. with higher activity.

In different C4 derivatives of D4T (R1=CH3, without R2, R3=H, and with double

bond C2=C3) was observed the following [1]: all the substituents on C4 that produce an

increase in the negative charge on O4, and as consequence on O2 and O4, and increase

of the dipole moment, and low furanose pucker P, increment the activity.

Simulating how the bonding process of D4TTP to viral DNA

in the cavity of the reverse transcriptase enzyme is

observed that substituents in 2-position should be very

small for steric interaction with residue Y115. Substituents

in 4-position can be large, but in 3-position should be

small.

In 5-halogenated derivatives of deoxythymidine (R1=

halogen) [2], a decrease in the calculated dipole moment, a lengthening of the O5’···O2

and O3’···O2 distances, an increment in the NBO negative charge on O2 and on the

halogen atom appear related to a decrease in the activity.

1 M. Alcolea Palafox, N. Iza, J. Mol. Struct. 2013, in press.

2 M. Alcolea Palafox, Struct. Chem. 2013, DOI: 10.1007/s11224-013-0225-1.

Fig. 1

Reuter, Christian – Thursday, 16:30 h

41

Electron diffraction and gas phase structures of several sulphur and nitrogen compounds

Christian G. Reuter, Yury V. Vishnevskiy and Norbert W. Mitzel

Bielefeld University, Universitätsstraße 25, Bielefeld, Germany

We will present details regarding the molecular structures of R-SCN where R can be CCl3,

CCl2F and -CH2Cl determined by means of GED experiments.1 For CCl2F and CH2Cl we

found two conformers each. The gas phase experiments for ClF2C-

C(O)-X with X = CN, NCO and NCS yielded only two conformers for

each the molecules.2,3 We are comparing X-C(O)-NCS, X-C(O)-SCN

(X = Cl, F) where only the Cl species have been refined yet. The

class of R-SNO compounds represented through R = CH3-CH2, CF3-

CH2 and (CH3)3C has also been investigated. Our most recent efforts

have been put into the investigation of CF3-CF2-C(O)-X with X = F,

Cl and I. In the gas phase structure of ClC(NO2)3 an exceptionally

short C-Cl bond has been reported.4,5 To extend this work the Br and

F derivatives were investigated.

Furthermore we present brief news about the Bielefeld experiment showing the progress in

Experiment automation.

1 L. A. Ramos, S. E. Ulic, R. Romano, M. F. Erben Y. V. Vishnevskiy, C. G. Reuter, N. W. Mitzel, H. Willner, H. Beckers, X. Zeng, E. Bernhardt, S. Tong, M. Ge, C. O. Della Védova, et al., J. Phys. Chem. A 2013, 117, 2383–2399.

2 L. A. Ramos, S. E. Ulic, Y. V. Vishnevskiy, N. W. Mitzel, H. Willner, C. O. Della Védova, R. Romano, H. Beckers, S. Tong, M. Ge, submitted.

3 L. A. Ramos, S. E. Ulic, R. M. Romano, S. Tong, M. Ge, Yu. V. Vishnevskiy, R. J. Berger, N. W. Mitzel, H. Beckers, H. Willner, C. O. Della Védova, Inorg. Chem. 2011, 50, 9650.

4 M. Göbel, B. H. Tchitchanov, J. S. Murray, P. Politzer, T. M. Klapötke et al., Nature Chem. 2009, 1(3), 229–235.

5 N. I. Sadova, N. I. Popik, L. V. Vilkov, A. Pankrushev, V. A. Shlyapochnikov, J. Chem. Soc. Chem. Commun. 1973, 3, 708.

Christen, Dines – Thursday, 17:00 h

42

Microwave-microwave-Double-Resonance spectroscopy of Acetone in the excited torsional state, ν17

Dines Christena, Melanie Unratha, Martina Müllera, Susan Obsta and Peter Gronerb

a Institut für Physikalische und Theoretische Chemie der Universität Tübingen, Auf der

Morgenstelle 18, 72076 Tübingen, Germany b Dept. of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110-2499,

USA

Acetone is so commonly known and used that one hardly expects any difficulty handling it.

The handling of the rotational spectrum, however, is difficult and tedious. The reason for

this complication is well known: The two internal rotors. But the analysis of the rotational

spectrum is still complicated, although the Hamiltonian – in principle – is known.

The combination of the symmetry numbers (σ1, σ2) = (0, 0) is non-generate. It

corresponds to the symmetry label AA in the conventional notation. The remaining

combinations form a fourfold degenerate set [(0, 1), (1, 0), (0, 2) and (2, 0)], corresponding

to label EE and two doubly degenerate pairs [(1, 1) and (2, 2)] corresponding to AE and

[(1, 2) and (2, 1)], corresponding to EA.

Because of the interactions, the sub-states have slightly different rotational energy levels.

This leads to rotational transitions split into four different components, one for each sub-

state. For the ground state, the width of this quartet splitting extends from a few MHz to

more than 1 GHz.

The narrowest quartet in ν17 is several hundred MHz wide, with most quartets reaching

several GHz.

Measurements and fits of transitions in the states AA, EE and AE will be presented.

Poster session

43

Molecular structure of α-alanine as studied by gas-phase electron

diffraction and quantum chemical calculation

Ekaterina P. Altova, Anatoly N. Rykov, Lyudmila V. Khristenko, Igor F. Shishkov

Chemistry Department, M.V. Lomonosov Moscow State University, Moscow, Russia

α-Alanine is of significant interest in the different fields of chemistry including structural

investigations. Till now the structure of gaseous α-alanine was investigated using the gas-

phase electron diffraction (GED) method. In an earlier study, the thermal-average structure

by GED1 and the structure by joint analysis using electron diffraction data and rotational

constants2 were determined. The purpose of the present research is the reinvestigation of

the molecular structure of α-alanine by the GED method and the determination of the

equilibrium structure taking into account vibrational corrections calculated from MP2/cc-

pVTZ. Тhe conformational vapour composition of α-alanine was estimated by the relative

Gibbs free energies and then identified by analyzing the GED data. The most stable α-

alanine form is shown in Fig.

This research was supported by the Russian Foundation for Basic Research (project no.

11-03-00716) and the Russian Foundation for Basic Research - Deutsche Forschungs-

gemeinschaft (project no. 12-03-91330).

Fig. The molecular structure of α-alanine

1 K. Iijima, B. Beagley, J. Mol. Struct, 1991, 248, 133.

2 K. Iijima, M. Nakano, J. Mol. Struct. 1999, 485–486, 255.

Poster session

44

Development of Mass Spectroscopy Capability with the Canterbury

Gas Electron Diffraction Apparatus

Sandra J. Atkinson and Sarah L. Masters

Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch 8140,

New Zealand, sarah.masters@canterbury.ac.nz

Recent research in the Canterbury gas electron diffraction (GED) group has focussed on

the investigation of gaseous molecular structures of new species generated in situ, either

by reaction or decomposition of a parent molecule. One side effect of this species

generation method is manifestation of several products of reaction or decomposition in the

vapour for analysis. Current research is focused on modifying the existing Canterbury

GED apparatus to incorporate a mass spectrometer (MS) so synchronous GED / MS data

can be obtained within a single experiment. This poster will focus on the key factors being

taken into consideration in such a design and the current setup concepts being

considered, highlighting the progress made to date.

Poster session

45

Tautomeric and conformational properties of acetylacetone,

CH3-C(O)-CH2-C(O)-CH3, by gas electron diffraction and quantum

chemical calculations

Natalya V. Belovaa, Nguen Hoang Tranga, Georgiy V. Giricheva, Heinz Oberhammerb

a Research Institute for Thermodynamics and Kinetics of Chemical Processes,

Ivanovo State University of Chemistry and Technology, Russia

b Institut für Physikalische und Theoretische Chemie,

Universität Tübingen, Germany

The calculated potential surface (with B3LYP/6-31G(d,p) approximation) for rotation of two

C(O)CH3 fragments in the keto form of acetylacetone possesses only one minimum of

energy corresponding to the (sc,sc) conformer with both τ(OCCC) torsional angles about

900. According to the calculations there is only one stable enol conformer. The predicted

relative energies (Δ(E)=Eketo-Eenol) and relative free energies (Δ(G0)=G°keto–G°enol)

depend strongly on the computational method. Whereas B3LYP/6-31G(d,p), B3LYP/aug-

cc-pVTZ and MP2/cc-pVTZ methods predict a strong preference of the enol tautomer,

MP2/6- 31G(d,p) method predict about 80% of the enol form at room temperature and

nearly equal amount of two tautomeric forms in overheated (671K) vapour.

The electron diffraction patterns and the mass spectra were recorded simultaneously at

two different temperatures of vapour. Analysis of GED intensities result in the presence of

100(3)% enol tautomer at 300(5)K, and of a mixture: 64(5)% enol and 36(5)% keto forms

at 671(5)K. The tautomeric composition at 671(5)K corresponds to a free Gibbs energy

difference Δ(G0)= 0.77(21) kcal/mol, that is surprisingly close to calculated with MP2/6-

31G(d,p) value (ΔG0 = 0.83 kcal/mol). The rh1 parameters of the enol form are very close

for both experimental results as well as for calculated (B3LYP/aug-cc-pVTZ and MP2/cc-

pVTZ) values. The enol ring possesses Cs symmetry with a strongly asymmetric hydrogen

bond.

This work was supported by Russian-German Cooperation Project

(RFBR N 12-03-91333-ННИО_а and DFG OB 28/22-1)

Poster session

46

Silacyclohexanes C5H10SiHCN, C5H10SiH(t-Bu),

C5H10Si(t-Bu)CN, and C5H10SiHF: DFT study

Yurii F. Sigolaev1, Sergei G. Semenov2, and Alexander V. Belyakov1

1 Technological Institute, 190013 Saint-Petersburg, Moskovskii prosp. 26, Russia

2 Saint-Petersburg State University, 198504 Saint-Petersburg, Russia

Titled compounds were studied at the M06-2X/aug-cc-pVTZ level of theory. It is

determined geometrical parameters, dipole moments, polarizabilities, first hyper-

polarizabilities and relative energies of the axial and equatorial conformers. For cyano

group and fluorine atom more preferable is axial position whereas for tert-butyl group

equatorial one. Polarizabilties of conformers are similar but optical anisotropy of equatorial

conformers of C5H10SiHCN and C5H10SiH(t-Bu) molecules is much larger than that of axial

conformers. Upon substitution in nitriles of C1 atom by Si atom hyper-polarizability is

increased by many times.

Poster session

47

Calculating accurate 13C chemical shifts of azines with density

functional methods and modest basis sets

Alexander S. Bunev, Vladimir E. Statsyuk, and Gennady I. Ostapenko

Togliatti State University, 445667 Togliatti, Belorusskaya 14, Russia

The purpose of this report is to convince practitioners of 13C NMR spectroscopy to

consider simple quantum chemical calculations as a viable option to aid them in the

assignment of their spectra. To this end, it is demonstrated, on a test set of 25

conformationally stable molecules azines of various kinds containing different positions the

nitrogen atoms, that, in contrast to what is claimed in the literature, large basis sets are not

needed to obtain rather accurate predictions of 13C NMR chemical shifts by quantum

chemical calculations. On the other hand, modelling the solvent by an SCRF-type

calculation may improve certain predictions significantly.

Exploratory calculations showed clearly that hybrid functionals are more apt to yield

accurate predictions of 13C chemical shifts than pure functionals. We decided to focus on

two groups of them, the popular B3LYP functional and the BLYP, B3PW91, PW1PW91

B98, BMK, HCTH, VSXC, M06, M06x, TPSSh, PBEh, X3LYP, LC-wPBE functionals. We

systematically explored double- and triple-ξ basis sets of the Pople (6-31G(d,p), 6-

31+G(d,p), 6-31++G(d,p), 6-311+G(d,p), 6-311++G(d,p), 6-311++G(2d,p)) and Dunning

families (cc-pVDZ, aug-cc-pVDZ, cc-pVTZ, aug-cc-pVTZ). The magnetic shielding

constants were computed using GIAO and GSGT methods. NMR calculations were carried

out both in the gas phase and in solution, using the polarizable continuum model PCM with

chloroform as the solvent.

Poster session

48

Quantum-chemical investigation of the structure and conformational

dynamics amidrazones some azoles

Alexander S. Bunev, Vladimir E. Statsyuk, and Gennady I. Ostapenko

Togliatti State University, 445667 Togliatti, Belorusskaya 14, Russia

Ab initio quantum-chemical calculations of equilibrium geometric parameters, vibrational

frequencies, and potential of internal rotation of amidrazones (scheme 1, 2) molecules in

their ground (S0) electronic states were performed.

Scheme 1. Structural formulas of conformers amidrazones

-150 -100 -50 0 50 100 150

0

2

4

6

8

10

E, kcal/m

ol

, degress

Scheme 2. The potential curve of internal rotation of amidrazones in S0 state.

Poster session

49

Heterocyclic aromatic N-Oxides:

the nature of semipolar N→O bond and reactive behavior

Nina I. Giricheva a, Natalya V. Belova b, Mikhail S. Fedorov a

a Ivanovo State University, Russia

b Research Institute for Thermodynamics and Kinetics of Chemical Processes,

Ivanovo State University of Chemistry and Technology, Russia

Molecular and electronic structure of some pyridine-N-oxides with -Cl, -CH3, -NO2, -OCH3,

-C2H2-Ph-N(CH3)2, and -C2H2-Ph-OCH3 as the substituents were studied by quantum

chemical calculations (DFT/B3LYP/cc-pVTZ, DFT/PBE0/cc-pVTZ and MP2/cc-pVTZ).

NBOanalysis was applied to description of semipolar N→O bond nature. The calculations

show that the introduction of acceptor (–NO2 substituent) in the molecule of N-oxide leads

to the significant lowering of HOMO and LUMO and, as the result, to growing of oxidation

affinity. The donor substituents (such as –CH3 and –OCH3)

favour the growing of N-oxides reductive properties. In the

molecules with π- conjugation between pyridine ring and the

substituent (-C2H2-Ph-N(CH3)2, and -C2H2-Ph-OCH3) the

LUMO goes down, whereas HOMO grows up, thereby the

excitation energy decreases. NBO-analysis interprets the

bonding σ(N-O) natural orbital as the linear combination of two

atomic hybrid orbitals: σ(N-O) = 0.7h(N)+0.7h(O). Due to the

polarization coefficients are equal, σ(N-O) is covalent bond.

Moreover, oxygen has three lone pairs: LP1= sp0.28, LP2= pπ and LP3 = pσ. There is

strong donor-acceptor interaction between lone pair of oxygen LP2 and anti-bonding π*(N-

C). The π-conjugation between the pyridine ring and LP2(O) provides the charge transfer

from oxygen to the ring. The introduction of strong donor substituent leads to the

lengthening of N→O bond and decreasing of N→O bond order. In this case electron

density on oxygen considerably increases, and complexing reactivity of the substance

grows up.

Poster session

50

Boron-based icosahedra: the structural consequences of

functionalising the cluster atoms, and their

removal

Drahomír Hnyk,a Derek A. Wann,b Heather E. Robertson,b Paul D. Lane,b Tomáš Baše,a

and Josef Holuba

a Institute of Inorganic Chemistry of the Academy of Sciences of the Czech Republic, v.v.i.,

250 68 Husinec-Řež, Czech Republic.

b School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh, EH9 3JJ,

UK.

Just as carbon forms hydrocarbons, its neighbour, boron, forms boron hydrides. Due to the

electron deficiency of boron, these boron hydrides do not resemble hydrocarbons in terms

of molecular shapes. The geometries of boron clusters are based on various polyhedra,

with the icosahedron being the most prominent. Indeed, closo-B12H122– represents one of

the most important building blocks in boron cluster chemistry and, moreover, is the most

symmetrical geometric arrangement of boron and hydrogen atoms (Ih point-group

symmetry). Departure from this symmetry may be achieved by replacing boron with

heteroatoms, such as carbon, in various positions within the cage, by replacing hydrogen

atoms with a variety of substituents (halogens and SH are often seen), and, finally, by

removing one, two, or more vertices, resulting in further classes of boron clusters, such as

nido or arachno.

Examples derived by substituting carbon atoms into closo-B12H122–, by replacing hydrogen

atoms with other atoms or moieties, and by the removal of the aforementioned carbon

atoms, were studied using gas electron diffraction in conjunction with ab initio and DFT

computational protocols of various quantities. These clusters are the subject of this

presentation.

Poster session

51

The structure of 1-Naphthalenesulfonyl chloride by gas electron

diffraction and quantum chemical calculations

Nina I. Giricheva,# Georgiy V. Girichev§*, Vjacheslav M. Petrov,# Marwan Dakkouri&,

Valentina N. Petrova,§ Sergey N. Ivanov#

#Ivanovo State University, Ivanovo 153025, Russia

§Ivanovo State University of Chemistry and Technology, Ivanovo 153000, Russia

&Department of Electrochemistry, University of Ulm, Germany

a-Naphthalenesulphonyl chloride, a-NaphSCl, was studied by gas-phase electron

diffraction (GED) and quantum chemical calculations (HF/6-311+G**, HF/aug-ccpVDZ,

B3LYP/cc-pVDZ, B3LYP/cc-pVTZ, B3LYP/aug-cc-pVDZ, B3LYP/aug-cc-pVTZ and

MP2/cc-pVDZ, MP2/cc-pVTZ). The calculations predict the existence of two conformers

with _1(I) and _s(II) symmetry. The more stable conformer I possesses an enantiomer.

The calculations showed, that in the vapor under experimental conditions the mole fraction

of conformer II with coplanar position of S-Cl bond and naphthalene frame is not more 1

mol %.

On the basis of the experimental data it was found that the gas phase over a-NaphSC at

370(5) K is represented by molecular species I of C1 symmetry in which the Ca-S-Cl plane

deviates from the perpendicular orientation relative to the naphthalene skeleton plane. The

following geometrical parameters (Å and degrees) of conformer I were obtained from the

experiment (uncertainties are in parantheses): rh1(C-H) = 1.082(6), rh1(C-C)av = 1.407(3),

rh1(C-S) = 1.764(5), rh1(S-O)av = 1.425(3), rh1(S-Cl) = 2.051(5), ÐC-Ca-C = 122.5(1)º,

ÐCa-S-Cl = 101.5(10)º; C9-C1-S-Cl = 71.4(21)°.

The calculated barriers for internal rotation of the sulphonyl chloride group exceed

considerably the thermal energy values corresponding to the temperatures of the GED

experiments. Natural bond orbitals (NBO) analyses of electron density distribution were

applied to explain the peculiarities of the molecular structure of the studied compound and

the deviation from the structures of b-NaphHal molecules and their benzene analogs.

We thank the Deutsche Forschungsgemeinschaft and Russian Fond of Basic

Researches for financial support of the Russian-German Cooperation (grants DFG OB

28/22-1 and RFBR 12-03-91333-HHИO-a)

Poster session

52

Gas-Phase Electron Diffraction and Quantum Chemical Study of b-

Naphthalenesulphonyl Fluoride and Chloride Molecular Structure

Nina I. Giricheva,# Vjacheslav M. Petrov,# Heinz Oberhammer,& Valentina N. Petrova,§

Marwan Dakkouri,d Sergey N. Ivanov,# Georgiy V. Girichev §*

#Ivanovo State University, Ivanovo 153025, Russia

§Ivanovo State University of Chemistry and Technology, Ivanovo 153000, Russia

&Institut für Physikalische und Theoretische Chemie, Universität Tübingen, 72076

Tübingen, Germany

dDepartment of Electrochemistry, University of Ulm, Germany

b-Naphthalenesulphonyl fluoride, b-NaphSF, and b-naphthalenesulphonyl chloride, b-

NaphSCl, were studied by gas-phase electron diffraction (GED) and quantum chemical

calculations (B3LYP and MP2 in combination with cc-pVDZ and aug-cc-pVDZ basis sets).

For each compound the calculations predict the existence of two conformers which are

enantiomers. On the basis of the experimental data it was found that the gas phase over

b-NaphSF and b-NaphSCl at 357(5) K and 395(5) K, respectively, consists of molecular

species of C1 symmetry in which the Cb-S-Hal plane deviates from the perpendicular

orientation relative to the naphthalene skeleton plane. The following geometrica

parameters (Å and degrees) were obtained from the experiment (uncertainties are in

parentheses): rh1(C-H) = 1.097(7), rh1(C-C)av. = 1.410(3), rh1(C-S) = 1.753(6), rh1(S-

O)av. = 1.414(4), rh1(S-F) = 1.559(5), ÐC-Cb-C = 122.8(3), ÐCb-S-F = 103.3(30); Ca-Cb-

S-F = 104(6) for b-NaphSF, and rh1(C-H) = 1.089(4), rh1(C-C)aver. = 1.411(3), rh1(C-S) =

1.757(5), rh1(S-O)aver.= 1.419(3), rh1(S-_l) = 2.053(4), ÐC-Cb-C = 122.8(1), ÐCb-S-Cl =

102.2(7), Ca- Cb-S-Cl =108(3) for b-NaphSCl. The calculated barriers to internal rotation

of the sulphonyl halide groups exceed considerably the thermal energy values

corresponding to the temperatures of the GED experiments. Natural bond orbital (NBO)

analyses of the electron density distribution were applied to explain the peculiarities of the

molecular structure of the studied compounds and the deviation from the structures of their

benzene analogs.

We thank the Deutsche Forschungsgemeinschaft and Russian Fond of Basic

Researches for financial support of the Russian-German Cooperation (grants DFG OB

28/22-1 and RFBR 12-03-91333- HHИO-a)

Poster session

53

The electronic and geometric structure of the benzenesulfonic acid

methyl ester and its 2- and 4-nitro-substituted molecules

Nina I. Girichevaa, Mikhail S. Fedorova, Sergey N. Ivanova, Georgiy V. Girichevb

a Ivanovo State University, Russia

b Ivanovo State University of Chemistry and Technology, Russia The study of gaseous 2- and 4-nitrobenzenesulfonic acid methyl esters (2- NBSAME, 4-

NBSAME) was carried out by gas-phase electron diffraction and mass spectrometric

(GED/MS) experiment (T=380(5) _ and T=376(5) K correspondingly). The recorded mass

spectra indicated that compounds vaporize without decomposition at the temperatures of

the GED/MS experiments, and the saturated vapour consists of monomers. Theoretical

calculations (B3LYP/cc-pVTZ, MP2/cc-pVTZ) showed that the molecule 4- NBSAME has

three conformers: one of them possesses Cs symmetry (II) and two mirror conformers of

C1 symmetry (I and I*). The conformational compo-

sition of the studied vapor (I : II : I* equals 16 : 68 :

16 mol%), and the structure of the conformers were

determined by the GED method for the first time. The

molecule 2-NBSAME has six conformers with relative

energies 0, 1.08, 0.89, 1.77, 2.22 and 2.91 kcal/mol

(B3LYP/cc-pVTZ). Four conformers were taken into

account at LS-analysis of GED data. NBO analysis of

electronic structure of the 4-NBSAME and

2-NBSAME conformers was performed and the explanation of stability for the certain

geometric configurations was proposed. The stabilization of near

orthogonal position of single S–O(CH3) bond relative to benzene ring is due to essential

donor-acceptor interaction between bonding π(C-C) orbital of benzene ring and

antibonding σ*(S-O(CH3)) orbital of SO3 group. The stabilization of asymmetric position of

O–C bond is substantially related to anomeric effect between lone pairs LP1(sp0.79) and

LP2(p) of oxygen atom O(CH3) and antibonding orbitals σ*(C-S) and σ* S=O).

Poster session

54

Substituent effect on the geometric and electronic structure of

benzenesulfonic acid

Nina I. Giricheva a, Mikhail S. Fedorov a, Sergey N. Ivanov a, Georgiy V. Girichev b

a Ivanovo State University, Russia

b Ivanovo State University of Chemistry and Technology, Russia A combined gas-phase electron diffraction/mass-spectrometric and quantum chemical

(B3LYP/ccpVTZ, MP2/cc-pVTZ) study of the molecular structures of paramethyl-

benzenesulfonic acid (4-MBSA) and meta-nitrobenzenesulfonic acid (3-NBSA) was carried

out. On the basis of mass spectrometric analysis, it was found that the substituted

benzenesulfonic acids are thermostable at least up to 431(3) K. The fragmentations of 4-

MBSA and 3-NBSA molecules under electron impact were analyzed. Quantum chemical

calculations show that the 4-MBSA molecule exists as an enantiomeric pair, which is

formed as a result of rotation of OH group about the S–O(H) bond. The 3-NBSA molecule

has two conformers with different orientations of the O–H bond with respect to the nitro

group and two corresponding enantiomers. The equilibrium configurations of 4-MBSA and

both conformers of 3-NBSA have similar structures of the SO3H group, with the O–H bond

eclipsing one of the S=O bonds. Selected experimental bond distances for 4-MBSA/3-

NBSA are (A°) rh1(C–C)av = 1.403(3)/1.395(4); rh1(C–S) = 1.765(5)/1.784(5); rh1(S=O)av

=1.433(4)/1.438(4); and rh1(S–O) = 1.618(4)/1.620(4). The potential functions for the

internal rotation of SO3H, OH, and CH3 or NO2 groups were calculated, and the transition

states between enantiomers (conformers) were determined. The influence of substituent’s

nature on molecular geometry as well as on the energies of frontier orbitals and red-ox

properties of the compounds is discussed. The inductive and mesomeric substituent

effects were estimated from the donor–acceptor interaction energies of the natural bond

orbitals of substituent and benzene frame. The correlation between group electro-

negativities and cooperative energetic characteristics of inductive and mesomeric effects

of substituents is shown.

Poster session

55

Analysis of electron diffraction data for 1,3,5-trinitrobenzene molecule

with consideration of equivalence of large amplitude motion

coordinates

Kochikov I.V., Khaikin L.S.,Tikhonov D.S., Grikina O.E.

M.V. Lomonosov Moscow State University,

Research Computer Center and Department of Chemistry

For the first time, on the basis of joint consideration of the results of electron

diffraction experiment, quantum chemical calculation at the MP2(full)/cc-pVTZ level and

vibrational spectra, a planar equilibrium conformation with D3h symmetry has been reliably

established for nonrigid 1,3,5-trinitrobenzene molecule, which is characterized by three

equivalent internal rotation coordinates of NO2 groups (, and angles correspond to the

turns of each of the nitro groups relative to the planar conformation). Total number of

configurations in case of a grid of angle values with 30° step is 123 = 1728. Since the

abovementioned coordinates transform into each other upon rotation around the C3 axis,

this number decreases to 32 forms that are not reducible to each other (see the Table).

Among them, only 14 configurations account for 99% of the distribution density at the

experimental temperature of 455К.

No. , , (°) Sym. Stat. Weight

ΔE kcal/mol

No. , , (°) Sym. Stat. Weight

ΔE kcal/mol

1 0,0,0 D3h 8 0.0 (ES) 17 90,0,0 C2v 24 4.11

2 90,90,90 D3h 8 13.46 18 0,90,90 C2v 24 8.59

3 30,30,30 D3 16 2.36 19 30,0,0 C2 48 0.84

4 60,60,60 D3 16 9.22 20 60,0,0 C2 48 2.93

5 0,30,150 Cs 48 1.76 21 0,30,30 C2 48 1.63

6 0,60,120 Cs 48 6.14 22 0,60,60 C2 48 6.00

7 30,90,150 Cs 48 6.05 23 30,30,60 C2 48 4.55

8 60,90,120 Cs 48 10.84 24 30,30,90 C2 48 5.92

9 0,30,60 C1 96 3.76 25 30,30,120 C2 48 4.88

10 0,30,90 C1 96 5.04 26 30,30,150 C2 48 2.68

11 0,30,120 C1 96 3.93 27 30,60,60 C2 48 6.83

12 0,60,90 C1 96 7.33 28 30,90,90 C2 48 9.62

13 30,60,90 C1 96 8.25 29 30,120,120 C2 48 7.16

14 30,60,120 C1 96 7.10 30 60,60,90 C2 48 10.70

15 30,60,150 C1 96 4.82 31 60,60,120 C2 48 9.56

16 30,90,120 C1 96 8.34 32 60,90,90 C2 48 12.11

This work was supported by the Russian Foundation for Basic Research, projects No. 11_03_00716_a and No. 12_03_91330_NNIO_a. The authors are thankful to the member of Hungarian Academy of Sciences, Prof. I. Hargittai, for the opportunity to use the high-quality recordings of scattering intensities for 1,3,5-trinitrobenzene, which were obtained under his guidance at the Budapest University of Technology and Economics.

Poster session

56

Gas-phase electron diffraction and quantum chemical investigation of

the molecular structure of benzamide

Inna N. Kolesnikovaa, Olga V. Dorofeevaa, Igor F. Shishkova, István Hargittaib a Department of Chemistry, M.V. Lomonosov Moscow State University, 11999, Moscow,

Russia b Hungarian Academy of Sciences and Department of Inorganic and Analytical Chemistry,

Budapest University of Technology and Economics, PO Box 91, H-1521, Hungary

The molecular structure of benzamide was determined by gas-phase electron diffraction (GED) and quantum chemical calculations (B3LYP and MP2 methods, cc-pVTZ basis set). The differences between a few selected geometrical parameters were constrained at values calculated at the MP2/cc-pVTZ level of theory. Consequences of steric effect of

the amino group were observed in r(C–C(C=O)), C2C1C7 and C2C1C7O8. The C=O bond is 0.02 Å shorter than that in the crystal and the C–N bond is 0.05 Å longer than that in the crystal. These differences are close to the corresponding differences found for formamide and acetamide.

Parameter a B3LYP/cc-pVTZ MP2/cc-pVTZ GED

C1–C7 1.501 1.487 1.509(4)

(C C)av 1.391 1.405 1.398(1)

C=O 1.218 1.219 1.223(3)

C–N 1.370 1.364 1.386(1)

(C–H)av 1.082 1.076 1.386(4)

(N–H)av 1.105 1.103 1.107(3)

C–C=O 122.0 122.1 121.6(16)

C–C=N 116.3 115.6 116.6(15)

C2–C1–C7 117.6 117.4 117.4(1)

(C C C)av 120.1 120.1 120.0(1)

(C C–H)av 120.1 120.2 120.2b

C7–N–H10 116.0 115.5 115.5b

C7–N–H11 120.8 119.6 119.6b

C2–C1–C7=O 19.1 19.9 19.5(107)

C1–C7–N–H10 -161.9 -161.3 -161.5(87)

Rf,% 2.4

aBond lengths are in Å and bond angles are in degrees; bAssumed at the value from MP2/cc-pVTZ calculations.

This research was supported by the Russian Foundation for Basic Research under the Grants No. 11-03-00716-a and No. 12-03-91330-NNIO_a.

Poster session

57

Molecular structure and conformation of 1,3,5-tris(trifluoromethyl)-

benzene as studied by gas-phase electron diffraction and quantum

chemical calculations

Inna N. Kolesnikovaa, Olga V. Dorofeevaa, Igor F. Shishkova, Rykov A. N.a, Karasev N. M.a, Heinz Oberhammerb

aDepartment of Chemistry, M.V. Lomonosov Moscow State University, 11999, Moscow,

Russia bInstitut für Physikalische und Theoretische Chemie, Universität Tübingen, 72076

Tübingen, Germany

The molecular structure of 1,3,5-tris(trifluoromethyl)benzene (1,3,5-TTFB) has been studied by gas-phase electron diffraction (GED) and quantum chemical calculations (B3LYP method with 6-31G(d,p), cc-pVTZ basis sets, and MP2 method with cc-pVTZ

basis set). The differences between geometrical parameters were constrained at values calculated at 6-31G(d,p) level. Quantum chemical calculations predict nearly free rotation of the three CF3 groups around Cphenyl-Cmethyl bonds. The GED intensities of 1,3,5-TFB can be fitted almost equally well with a single conformer with C1 symmetry (Rf = 4.2%), or with a mixture of 39(10)% C3h, 37(10)% Cs, and 24(10)% C3v

conformers (Rf = 4.4%). The GED results are in a good agreement with ab initio calculations.

Molecular structure of 1,3,5-TFB obtained by gas-phase electron diffraction and quantum chemical calculations

a Bond lengths are in Å and bond angles are in degrees; α=C2–C1–C7–F12, β=C4–

C3–C8–F15, γ C6–C5–C9–F18

This research was supported by the Russian Foundation for Basic Research under the Grants No. 11-03-00716-a and No. 12-03-91330-NNIO_a

Para-meter a

B3LYP/6-31G(d,p) GED

1 conf.

mixture 1 conf.

mixture

C3h Cs C3v C3h Cs C3v

(C–F)av 1.347 1.345 1.347 1.347 1.347(2) 1.346(2) 1.348(2) 1.347(2)

(C C)av 1.389 1.391 1.389 1.389 1.388(5) 1.392(5) 1.392(5) 1.392(5)

(C–C)av 1.509 1.508 1.509 1.509 1.511(5) 1.510(5) 1.508(5) 1.511(5)

α 33.0 59.5 29.1 29.6 19.9(10) 60.7(16) 29.7(24) 29.0

β 75.8 59.5 30.8 -29.6 56.2(10) 60.7(16) 31.4 -29.0

γ 75.9 59.5 -151.5 -29.6 77.1(10) 60.7(16) -152.4 -29.0

P,% 100 29 37 34 100 39(10) 37(10) 24(10)

Rf,% 4.2 4.4

C6

C5C4

C3

C2

C1

C7

C8C9

F10

F11F12

F13

F14F15

H19H21

H20

F18

F17F16

Poster session

58

Large-amplitude motions for methyl trifluoroacetate and 2, 5-

dimethylfuran by GED, MW and quantum chemical calculation

Nobuhiko Kuzea, Atsushi Ishikawaa, Yuya Onoa, Hiroshi Takeuchib and Shigehiro Konakab

aSophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan

E-mail: n-kuze@sophia.ac.jp

bDepartment of Chemistry, Faculty of Science, Hokkaido University, Sapporo

060-0810, Japanw

Gas electron diffraction (GED) and the vibrational study of methyl trifluoroacetate

(CF3COOCH3) were reported in 20091. The precise molecular structure of this compound

was determined by the University of Edinburgh in this paper. We have carried out the GED

of methyl trifluoroacetate at Hokkaido University independently. We found that our GED

data was reproduced well if we considered the large-amplitude motion of the CF3 group. In

this work, we will present the dynamical model of this compound by analysing the GED

data and rotational constant. Jones et al. have been observed the microwave (MW)

spectrum and determined the rotational constants of this molecule2. We have observed

and assigned some additional absorption lines for our MW spectrum, the results were

used for the combined analysis of GED and MW data.

Another example for the dynamic model analysis of GED data is 2, 5-dimethylfuran which

is known as the candidate for the biofuel. We are trying to determine the potential

parameters of the internal rotations for the two methyl groups. Details of the data analysis

as well as the LCNMR data analysis will be presented.

1 M. E. D. Lestard, M. E. Tuttolomondo, E. L. Varetti, D. A. Wann, H. E. Robertson, D. W.

H. Rankin and A. B. Altabefa, J. Raman Spectrosc., 2009, 40, 2053.

2 G. I. L. Jones, T. D. Summers and N. L. Owen，J. Chem. Soc., Faraday Trans., 1973,

70, 100.

Poster session

59

Molecular structure study of some methyl derivatives of uracil

by electron diffraction method and high-level ab initio calculations

Ilya I. Marochkin a, Natalja Vogt b, Anatolii N. Rykov a, Olga V. Dorofeeva a, Jürgen Vogt b,

and Igor F. Shishkov a

a Moscow State University, Chemistry Department, Moscow, Russia;

b University of Ulm, Chemical Information Systems, Ulm, Germany

The determination of the molecular structure of 1-methyluracil and 1-methylthymine has

been carried out by gas-phase electron diffraction (GED) method and high-level ab initio

calculations (up to CCSD(T)). According to results of the MP2/cc-pVTZ calculations, both

molecules exist as a single conformer with a planar skeleton and a methyl group at the N

atom in a staggered position with respect to the N-C(=O) bond (the second methyl group

in 1-methylthymine has also staggered conformation relative the C-C(=O) bond) as shown

in Fig. 1 (Cs total symmetry). In the GED analysis for each molecule, the differences

between the N-C bond lengths and between the C-C bond lengths are fixed at the values

of the calculated “best ab initio” structure, and the large-amplitude motion of the CH3 group

at the N atom is described by a dynamic model yielding essentially lower R factor than a

static one. The equilibrium structure has been determined from experimental data taking

into account harmonic and anharmonic vibrational corrections calculated from

MP2/cc-pVTZ quadratic and cubic force fields, respectively.

The equilibrium structural parameters of 1-methyluracil and 1-methylthymine obtained from

GED data are found to be very close to those of the “best ab initio” structure.

This work was supported by the Russian Foundation for Basis Research Grant

№ 11-03-00716-а and 12-03-91330-NNIO-а and by the German Barbara Mez-Starck

Foundation.

Fig. 1. The molecular structure of 1-methylthymine (left) and 1-methyluracil (right)

Poster session

60

Electron-nucleus overlap & parity-violating effects in PbF, YbF, and RbF

Zachary Glassman1, Benjamin Girodias1, Richard Mawhorter1,

Timothy Steimle2, Michaela Jahn3, and Jens-Uwe Grabow3

1Physics Dept., Pomona College, Claremont, CA 91711 USA

2Chemistry Dept., Arizona State University, Tempe, AZ 85287 USA

3Institut für Physikalische Chemie, Leibniz-Universität, Hannover D 30167

The shape or electric dipole moment of the

electron (eEDM) is a fascinating mystery which could

prove to unlock a path to physics beyond the standard

model. While the standard model predicts that the eEDM

is less than 10-40 e·cm, the majority of other theories and

models predict the eEDM to be much larger. The current

limiting measurement is on the order of 10-27 e·cm, made

by a team from Imperial College on the open shell

molecule YbF. Current experiments are focusing on this

and other heavy free radicals, which in weak external polarizing fields can exhibit very

large internal effective electric fields (~10 - 100 GV/cm) near the nucleus of the larger

atom. Observing the nuclear electric hyperfine structure (eQq) for YbF will help constrain

the wave functions used to calculate these huge internal fields. There is also a very small

but nonzero probability that the unpaired electron will be near and even inside the nucleus,

resulting in a slight perturbation to the nuclear quadrupole moment for closed shell

molecules like RbF as well as in shifts due to parity-violating (PV) effects due to the

relativistic electron-nucleus interaction in molecules like YbF and PbF. These include the

larger spin-dependent anapole moment as well as the tiny spin-independent eEDM. We

use Fourier transform microwave spectroscopy with sub-kilohertz resolution to explore the

sensitivity of these molecules to these subtle but fascinating effects, which is motivated in

the figure by Neil Shafer-Ray showing the handedness of molecular rotation in an orienting

external field.

Poster session

61

The structure of free copper (II) 2,9,16,23-tetra-tert-butyl-

phthalocyanine: preliminary DFT calculations

Oleg A. Pimenov, Georgiy V. Girichev and Vladimir E. Maizlish

Ivanovo State University of Chemistry and Technology, 153 000 Ivanovo, Engels av. 7,

Russia

The DFT calculations of copper (II) 2,9,16,23-tetra-tert-butyl-phthalocyanine (CuTTBPc)

molecule were performed. Two

different approaches (UB3LYP and

ROB3LYP) were employed with 6-

31G* basis set, and two force fields

were used to make the starting

molecular model in gas electron

diffraction (GED) refinement. The

calculations UB3LYP/cc-pVTZ (N, C,

H) with Stuttgart relativistic

pseudopotential for Cu are carried

out also.

The DFT optimized geometry of CuTTBPc has the symmetry C4h (Fig). In the

equilibrium configuration the C-C bond of the tert-butyl group eclipses the C-C bond of the

benzene ring in macrocycle. The computations predict the internal rotation of the tert-butyl

groups to be independent. The barrier of internal rotation is 3.3 kJ/mol (UB3LYP/6-31G*)

for single tert-butyl group. The distance between neighbouring tert-butyl groups is about 9

Å. The thermal energy of CuTTBPc for the temperature of GED experiment (T=744 K) RT=

6.2 kJ/mol, and tert-butyl groups rotation is practically free at this conditions.

The geometries of CuTTBPc molecule from restricted and unrestricted approaches

are identical. The structural parameters of macrocycle frame of CuPc are close to

geometry of macrocycle frame in CuTTBPc. Thus, the tert-butyl substituents have weak

influence on the phthalocyanine macrocycle structure.

Authors thank the Russian Foundation for Basic Research, RFBR (Grant 13-03-

00975a) for financial support.

Poster session

62

The molecular structure of zinc(II) etioporphyrin-II:

a gas-phase electron diffraction and quantum chemical study

Alexander Pogonin a, Natalya Tverdova a, Anatoly Ischenko b and Georgiy Girichev a

a Ivanovo State University of Chemistry and Technology, Research Institute of Chemistry

of Macroheterocyclic Compounds, F. Engels av. 7, Ivanovo, 153000, Russian Federation

b Moscow Lomonosov State University of Fine Chemical Technologies, Vernadskogo 86,

Moscow 119517, Russian Federation

Gas-phase molecular structure of zinc(II) etioporphyrin-II (ZnEP-II) has been studied by

a synchronous gas-phase

electron diffraction and mass

spectrometry method and DFT

calculations using the B3LYP and

PBE functionals with pVTZ basis

sets for describing H, C, N atoms

and cc-pVTZ for describing Zn

atom.

The mass spectrum consists of

two groups of peaks corres-

ponded to single and double charged parent ion and ions formed by consecutive

removal of hydrocarbon groups (-СH3, –С2H5, –С2H4) by an electron impact.

The molecule ZnEP-II was found to possess quasiplanar geometry of macro-

heterocycle. Five conformers of this compound have been studied by DFT computations.

Energetic differences of these conformers are less than 0.1 kJ/mol. Rotation barriers of

ethyl group are 15.7 and 20.6 kJ/mol (B3LYP). Every bonded internuclear distances in

different conformers are practically the same, and it is impossible to distinguish сonformers

from each other using GED-method.

Structural parameters of the ZnEP-II molecule yielded by the GED are generally in good

agreement with DFT calculations and X-ray data on crystalline zinc(II) octaethylporphyrin

(ZnOEP).

Authors thank the Russian Foundation for Basic Research, RFBR (Grant 13-03-00975a)

for financial support.

Poster session

63

Ab initio calculations of DNA nucleobases and simulation of electron

diffraction patterns

K. Siddiqui1,2, G. Corthey1, T. Hasegawa1, S. Hayes1, K. Pichugin1, G. Sciaini1, R.J.D.Miller1 and B. J.Whitaker2

1Max Planck Research Department for Structural Dynamics, Center for Free electron

Laser Science, University of Hamburg. Luruper Chaussee 149, 22761, Hamburg,

Germany.

2School of Chemistry, Unviersity of Leeds, Leeds LS2 9JT, UK.

Deoxyribonucleic acid (DNA) bases, i.e., adenine, thymine, cytosine and guanine are the

building blocks of life. They exhibit interesting photophysics in the ultra-violet/visible range

in that, after excitation, they are rapidly deactivated (τdeactivation ~ 100 fs – 1 ps). This

ultrafast deactivation is proposed to be the reason behind DNA’s remarkable photostability

and evolution of life on Earth [1]. Ultrafast Electron Diffraction (UED) is a technique ideally

suited to studying such processes with both atomic spatial and femtosecond time

resolution [2]. We are interested in trying to identify key states of DNA bases that play a

part in the deactivation and hence elucidate the mechanism of DNA photostability using a

combination of Ab inito calculations at the complete active space self-consistent field

(CASSCF) level and UED. In this poster, we present some results from Ab initio

calculations done on adenine and thymine. The structures obtained from these

calculations are used to simulate electron diffraction patterns as an experimental feasibility

study.

1 Hernadez et al ,Chem. Rev. 2004, 104,1977–2019.

2 G.Sciani and R.J.D Miller, Rep. Prog. Phys. 2011, 74, 96101.

Poster session

64

Molecular structure of thulium tris-dipivaloylmethanate, Tm(thd)3, by

gas electron diffraction (GED) and DFT calculations.

Natalya V. Belova, Valery V.Sliznev, Georgiy V.Girichev, Oleg A. Pimenov

Research Institute for Thermodynamics and Kinetics of Chemical Processes,

Ivanovo State University of Chemistry and Technology, Russia

Geometrical and electronic structure,

intramolecular rearrangements and the internal

rotation of thulium tris-dipivaloylmethanate,

Tm(thd)3, were studied by gas phase electron

diffraction and quantum chemical calculations.

Theoretical calculations were performed using

DFT method (B3LYP, PBE0) and cc-pVTZ basis

sets. Core shells of Tm including partially

occupied 4f-shell were described by Stuttgart

relativistic pseudopotential. NBO-analysis was applied to description of chemical bonding.

The calculations show that the complex, Tm(thd)3, possess the equilibrium

configuration of D3 symmetry (fig.). The relative energy of D3h structure corresponding to

the barrier on the path of the intramolecular rearrangement is 7.4 (B3LYP) or 4.7 kJ/mol

(PBE0). In the equilibrium configuration the C-C bond of the tert-butyl group eclipses the

C-C bond of the chelate ring. The structure with eclipsed C-O bond corresponds also to

the local minimum on PES. Relative energies of these configurations are 3.4 for single tert-

butyl group and 22.3 kJ/mol for all tert-butyl groups.

The interpretation of ED data was performed only for D3 configuration. Quantum

chemical structure is close to experimental rh1 parameters. Obtained geometrical

parameters of Tm(thd)3 molecule were compared with available data for similar

compounds.

Poster session

65

Molecular structure of L-tryptophan

Valeriya V. Tyunina, Nina I. Giricheva*, and Georgiy V. Girichev

Ivanovo State University of Chemistry and Technology, 153000 Ivanovo, Engels av. 7,

Russia

* Ivanovo State University, 153025 Ivanovo, Ermak st. 39, Russia

Amino acids are model compounds of proteins taking part in many important biochemical

processes such as neuroregulation, enzyme catalysis, etc. These substances are well-

known to exist as zwitterions in the solid state and aqueous solution, amino acids,

however, having a molecular form in the gas phase. Besides, amino acid molecule has a

low symmetry and many rotational degrees of freedom. Therefore, molecules have a large

number of different low energy conformers on the potential energy surface. In this work

investigation of saturated vapour of L-tryptophan was carried out by gas electron

diffraction and mass spectrometry at T=495 K. Mass spectra have a typical fragmentation

for amino acids: elimination of side chain and carboxylic group and registration of ions:

COOH+, NH2CHCO+, NH2CH+. The major peaks were observed at m/z = 130 (C9H8N+) and

m/z = 204 (molecular form). Enthalpy of sublimation was found by thermodynamics law II:

sH(Trp)=184(3) kJ/mol at T=450 K. The geometries, energies and vibrational frequencies

of tryptophan conformers were calculated using B3LYP/cc-pVTZ level of theory.

Conformers have different orientations of carboxylic and amine group, backbone and

indole fragment to each other. The most stable conformers of tryptophan have

intramolecular hydrogen bond between carboxylic and amide group. It should be noted

that 8 conformers should be used at LS refinement of GED data. These conformers can be

divided at two groups: distinguishable [with different torsion angle C(OOH)-C(HNH2)-

C(H2)-C(ind)] and indistinguishable [with different torsion angles H-N-C-C and H-O-C-C] by

GED. It is shown the capabilities and limitations of GED method at determination the

structure of molecules with large number of conformers.

This study was supported by Russian Foundation for Basis Research (project № 12-03-

31758mol_а).

Poster session

66

Modernization of electron diffractometer EMR-100M

Nikolai M. Karasev a, Maxim A. Abaev a, Alexander M. Makurenkov a, Natalja Vogt b,

Werner Leikam c, Jürgen Vogt b, and Igor F. Shishkov a

a Moscow State University, Chemistry Department, 119991 Moscow, Russia;

b University of Ulm, 89069 Ulm, Germany;

c Staib Instruments, 85416 Langenbach, Germany

After introducing the imaging plate registration system1, the experimental equipment in the

electron diffraction (ED) laboratory of the Moscow State University has been further

modernized. The electron diffractometer EМR-100М, originally produced in Sumy

(Ukraine) the solid state electron diffraction in 1981, has been equipped with the custom-

made electron gun system GDS60, a new evaporator (similar to that constructed for EG-

100 diffractometer by A. A. Ivanov) with a medium-temperature nozzle and two separate

inlet valves for the gas standard and the sample, as well as a new sector construction.

Moreover, the turbo molecular pump system (with HiPace80 pump), which allows to reach

the vacuum during experiment up to 10-7 mbar, has been

installed. The functionality of the modernized electron

diffraction system has been proven on the test object

CCl4. Its advantages will be discussed.

This work has been carried out in the cooperation

between the Electron Diffraction laboratory of Moscow

State University and the section Chemical Information

Systems and has been supported by the Russian

Foundation for Basis Research (Grants № 11-03-00716-а

and 12-03-91330-NNIO-а) and by the German Barbara

Mez-Starck Foundation.

Fig.: Photograph of the modernized gas electron diffractometer EМR-100М at the Moscow

State University.

1 N. Vogt, R. Rudert, A. N. Rykov, N. M. Karasev, I. F. Shishkov, and J. Vogt: Struct.

Chem., 2011, 22, 287.

Poster session

67

Comparative analysis of structures of succinimide and its N-derivatives

in crystalline and gaseous phases

L.A. Zasurskaya, A. E. Obodovskaya

Chemistry Department of M.V. Lomonosov Moscow State University, Moscow, Russia

A comparison of molecular structures of succinimide (Su) and its N-derivatives

(CH2CO)2NX in gaseous phase (X = CH3, Cl, Br) and in crystals (X = H, OH, Cl, Br, I, CH3

and NO2) was performed using GED1 and X-ray (CSD)2 experimental data.

In all molecules, both in gaseous and crystalline phases, the lengths of N–X bonds are

nearly equal. For all molecules GED shows that the heterocycle is planar (СССС = 0),

while in crystals it is almost planar only in Su (СССС = 2.7). The values of СССС are

slightly larger in its N-derivatives: 5.8 (OH), 8.1 (Cl), 4.0 (Br), 7.1 (I), 11.1 (CH3)

and 10.5 (NO2), which indicates the flexibility of the cycle. The analysis of molecular

packing in the Su crystal shows that centrosymmetrical dimers of molecules linked by H-

bonds of the NH٠٠٠O type are formed in the structure. The dimers are united into "parquet"

layers by 4 short C٠٠٠O contacts (О٠٠٠centroid distance is 2.880 ), while the stacking of

the layers produces the crystal (Pbca, Z = 8). NO2–Su crystallizes in the same space

group. In this case, however, the structure is formed by chains and layers united by

CH٠٠٠O bonds. The structures with X = OH, Cl and Br (P212121, Z = 4) are made of

ribbons, in which molecules are related by axis 21. In ОН-Su ribbons are formed by strong

intermolecular О-Н٠٠٠О bonds, C-H٠٠٠O bonds and short С٠٠٠О contacts (like in Su). In

isostructural Cl-Su and Br-Su the molecules in the ribbons are united not only by C-H٠٠٠O

bonds, but also by short Hal٠٠٠O and Hal٠٠٠Hal contacts. The tetragonal structure of I–Su

(P41, Z = 4) is rare for molecular crystals. Short contacts I٠٠٠О make molecules related by

axis 41 form helices united by C-H٠٠٠O bonds. In monoclinic structure СН3-Su (P21/n, Z=4)

molecules related by axis 21(Y) form ribbons due to CMe–H٠٠٠O interactions and layers due

to CH٠٠٠O bonds.

1 Yu. V. Vishnevskiy, L. V. Vilkov, A. A. Ivanov, V. V. Kuznetsov, N. N. Makhova, N. Vogt,

J. Vogt, IV-th National Crystal Chemistry Conference, Chernogolovka (Russia), 2006, 322.

2 F. H. Allen, Acta Crystallogr. B. 2002, 58, 380.

Poster session

68

The structure of a thiadiazole-containing expanded

heteroazaporphyrinoid determined by gas-phase electron diffraction

and DFT calculations

Yuriy Zhabanov, Alexander Zakharov, Sergei Shlykov, Mikhail Islyaikin, and Georgiy

Girichev

Ivanovo State University of Chemistry and Technology, Research Institute of Chemistry of

Macroheterocyclic Compounds, F. Engels av. 7, Ivanovo, 153000, Russian Federation

Macroheterocyclic compounds of ABABAB type containing 1,3,4-thiadiazole rings are a

relatively new class of expanded porphirinoids.1, 2 In 2008 we reported3 the first direct

characterization of the molecular structure of the tert-butyl-substituted macrocycle

(C42H39N15S3) by a synchronous gas electron diffraction and mass spectrometric

experiment and DFT calculations. In this study we have investigated the unsubstituted

(C30H15N15S3, see the figure) compound by a synchronous gas electron diffraction and

mass spectrometric experiment and density functional theory calculations using the B3LYP

and M06 hybrid functionals and cc-pVTZ basis sets. The six tautomers of this compound

have been studied by DFT computations. The molecule

has an equilibrium structure of D3h symmetry with a

planar macrocycle and the thiadiazole rings oriented in

such a way that the sulfur atoms point outwards from

the inner cavity. The existence of hydrogen bonds was

confirmed by NBO analysis. According to the NBO

analysis there is an interaction between lone pairs of N

atoms in thiadiazole rings and anti-bonding N-H

orbitals.

This work was supported by a grant RFBR 13-03-00975

1 M. K. Islyaikin, E. A. Danilova, L. D. Yagodarova, M. S. Rodríguez-Morgade, T. Torres,

Org. Lett. 2001, 3, 2153.

2 N. Kobayashi, S. Inagaki, V. N. Nemykin, T. Nonomura, Angew. Chem., Int. Ed. 2001,

40, 2710.

3 A. V. Zakharov, S. A. Shlykov, S. A. Bumbina, E. A. Danilova, A. V. Krasnov, M. K.

Islyaikin, G. V. Girichev, Chem. Commun., 2008, 3573.

Poster session

69

REGAE: Towards Ultrafast electron diffraction and dynamic microscopy Dongfang Zhang,1 Stephanie Manz,1 Albert Casandruc,1 Julian Hirscht,1 Sercan Keskin,1

Jeff Nicholls,4 Kostyantyn Pichugin,1 Stuart Hayes,1 Santosh Jangam,1 Taisuke

Hasegawa,1 Alexander Marx,1 Shima Bayesteh,2 Hossein Delsim-Hashemi,2 Matthias

Felber,2 Holger Schlarb,2 Matthias Hoffmann,2 Markus Huening,2 Tim Gehrke,3 Frank

Mayet,3 Max Hachmann,3 Gustavo Moriena,4 Sascha Epp,1 Masaki Hada,1 Klaus

Floettmann,2 R. J. Dwayne Miller,1,4

1Max Planck Research Department for Structral Dynamics, Center for Free Electron Laser

Science, University of Hamburg, Luruper Chausee 149, 22761 Hamburg, Germany

2Deutsches Elektronen-Synchrotron, Notkestrasse 85, 22607, Hamburg, Germany

3Institute for Experimental Physics, Center for Free Electron Laser Science, University of

Hamburg,, Luruper Chaussee 149, 22761 Hamburg, Germany

4Department of Chemistry and Physics, University of Toronto, 80 St. George st., Toronto,

Ontario M5S3H6, Canada

The Relativistic Electron Gun for Atomic Exploration (REGAE) has been designed to study

structural dynamics in solid, solution and gas phase on the femtosecond timescale.

REGAE is based on rf-accelerated electron source generating 2–5 MeV electron bunches.

The electron energy, beam size, pulse duration and coherence length in REGAE were

theoretically characterized with a space charge tracking algorism (ASTRA) 1. Exploiting

arebunching rf cavity, the electron pulses from REGAE are expected to be as short as 7 fs

(rms) with high electron density (106 electron/pulse), small transverse emittance (6×10−3

mm mrad) and long coherence length (~30 nm). The excellent temporal and spatial

resolution of this relativistic electron source will open up a new frontier for ultrafast electron

diffraction and dynamic microscopy.

1 K. Flöttmann, Astra, http://tesla.desy.de/~meykopff/.