1
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Solov’yov AV, Verkhovtsev AV, Mason NJ, Amos RA, Bald I, Baldacchino G, Dromey B, Falk M, Fedor J, Gerhards L, Hausmann M, Hildenbrand G, Hrabovský M, Kadlec S, Kočišek J, Lépine F, Ming S, Nisbet A, Ricketts K, Sala L, Schlathölter T, Wheatley AEH, Solov’yov IA. Condensed Matter Systems Exposed to Radiation: Multiscale Theory, Simulations, and Experiment. Chem Rev 2024; 124:8014-8129. [PMID: 38842266 PMCID: PMC11240271 DOI: 10.1021/acs.chemrev.3c00902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 05/02/2024] [Accepted: 05/10/2024] [Indexed: 06/07/2024]
Abstract
This roadmap reviews the new, highly interdisciplinary research field studying the behavior of condensed matter systems exposed to radiation. The Review highlights several recent advances in the field and provides a roadmap for the development of the field over the next decade. Condensed matter systems exposed to radiation can be inorganic, organic, or biological, finite or infinite, composed of different molecular species or materials, exist in different phases, and operate under different thermodynamic conditions. Many of the key phenomena related to the behavior of irradiated systems are very similar and can be understood based on the same fundamental theoretical principles and computational approaches. The multiscale nature of such phenomena requires the quantitative description of the radiation-induced effects occurring at different spatial and temporal scales, ranging from the atomic to the macroscopic, and the interlinks between such descriptions. The multiscale nature of the effects and the similarity of their manifestation in systems of different origins necessarily bring together different disciplines, such as physics, chemistry, biology, materials science, nanoscience, and biomedical research, demonstrating the numerous interlinks and commonalities between them. This research field is highly relevant to many novel and emerging technologies and medical applications.
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Affiliation(s)
| | | | - Nigel J. Mason
- School
of Physics and Astronomy, University of
Kent, Canterbury CT2 7NH, United
Kingdom
| | - Richard A. Amos
- Department
of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, U.K.
| | - Ilko Bald
- Institute
of Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - Gérard Baldacchino
- Université
Paris-Saclay, CEA, LIDYL, 91191 Gif-sur-Yvette, France
- CY Cergy Paris Université,
CEA, LIDYL, 91191 Gif-sur-Yvette, France
| | - Brendan Dromey
- Centre
for Light Matter Interactions, School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN, United Kingdom
| | - Martin Falk
- Institute
of Biophysics of the Czech Academy of Sciences, Královopolská 135, 61200 Brno, Czech Republic
- Kirchhoff-Institute
for Physics, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
| | - Juraj Fedor
- J.
Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - Luca Gerhards
- Institute
of Physics, Carl von Ossietzky University, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
| | - Michael Hausmann
- Kirchhoff-Institute
for Physics, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
| | - Georg Hildenbrand
- Kirchhoff-Institute
for Physics, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
- Faculty
of Engineering, University of Applied Sciences
Aschaffenburg, Würzburger
Str. 45, 63743 Aschaffenburg, Germany
| | | | - Stanislav Kadlec
- Eaton European
Innovation Center, Bořivojova
2380, 25263 Roztoky, Czech Republic
| | - Jaroslav Kočišek
- J.
Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - Franck Lépine
- Université
Claude Bernard Lyon 1, CNRS, Institut Lumière
Matière, F-69622, Villeurbanne, France
| | - Siyi Ming
- Yusuf
Hamied Department of Chemistry, University
of Cambridge, Lensfield
Road, Cambridge CB2 1EW, United Kingdom
| | - Andrew Nisbet
- Department
of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, U.K.
| | - Kate Ricketts
- Department
of Targeted Intervention, University College
London, Gower Street, London WC1E 6BT, United Kingdom
| | - Leo Sala
- J.
Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - Thomas Schlathölter
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, 9747 AG Groningen, The Netherlands
- University
College Groningen, University of Groningen, Hoendiepskade 23/24, 9718 BG Groningen, The Netherlands
| | - Andrew E. H. Wheatley
- Yusuf
Hamied Department of Chemistry, University
of Cambridge, Lensfield
Road, Cambridge CB2 1EW, United Kingdom
| | - Ilia A. Solov’yov
- Institute
of Physics, Carl von Ossietzky University, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
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2
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Li K, Ďurana J, Kocábková B, Pysanenko A, Yan Y, Ončák M, Fárník M, Lengyel J. Hydrated Formic Acid Clusters and their Interaction with Electrons. Chemphyschem 2024; 25:e202400071. [PMID: 38372591 DOI: 10.1002/cphc.202400071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 02/18/2024] [Accepted: 02/19/2024] [Indexed: 02/20/2024]
Abstract
We investigate ion formation in hydrated formic acid (FA) clusters upon collision with electrons of variable energy, focusing on electron ionization at 70 eV (EI) and low-energy (1.5-15 eV) electron attachment (EA). To uncover details about the composition of neutral clusters, we aim to elucidate the ion formation processes in FAM ⋅ WN clusters initiated by interaction with electrons and determine the extent of cluster fragmentation. EI predominantly produces protonated [FAm+H]+ ions, and in FA-rich clusters, the stable ring structures surrounding H3O+ ions are formed. In contrast, EA leads to a competition between the formation of intact [FAm ⋅ Wn]- and dissociated [FAm ⋅ Wn-H]- fragment ions, influenced by the cluster size, level of hydration, and electron energy. Our findings reveal a predisposition of low-energy EA towards forming [FAm ⋅ Wn]-, while higher electron energies tend to favor the formation of [FAm ⋅ Wn-H]- due to intracluster ion-molecule reactions. The comparison of positive and negative ion spectra suggests that the mass spectra of FA-rich clusters may indicate their actual size and composition. On the other hand, the more weakly bound water evaporation from the clusters depends strongly on the ionization. Thus, for the hydrated clusters, the neutral cluster size can hardly be estimated from the mass spectra.
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Affiliation(s)
- Kevin Li
- Lehrstuhl für Physikalische Chemie, TUM School of Natural Sciences, Technische Universität München, Lichtenbergstraße 4, 85748, Garching, Germany
| | - Jozef Ďurana
- J. Heyrovský Institute of Physical Chemistry v.v.i., Czech Academy of Sciences, Dolejškova 3, 18223, Prague, Czech Republic
| | - Barbora Kocábková
- J. Heyrovský Institute of Physical Chemistry v.v.i., Czech Academy of Sciences, Dolejškova 3, 18223, Prague, Czech Republic
| | - Andrij Pysanenko
- J. Heyrovský Institute of Physical Chemistry v.v.i., Czech Academy of Sciences, Dolejškova 3, 18223, Prague, Czech Republic
| | - Yihui Yan
- Lehrstuhl für Physikalische Chemie, TUM School of Natural Sciences, Technische Universität München, Lichtenbergstraße 4, 85748, Garching, Germany
| | - Milan Ončák
- Institut für Ionenphysik und Angewandte Physik, Leopold-Franzens Universität Innsbruck, Technikerstrasse 25, A-6020, Innsbruck, Austria
| | - Michal Fárník
- J. Heyrovský Institute of Physical Chemistry v.v.i., Czech Academy of Sciences, Dolejškova 3, 18223, Prague, Czech Republic
| | - Jozef Lengyel
- Lehrstuhl für Physikalische Chemie, TUM School of Natural Sciences, Technische Universität München, Lichtenbergstraße 4, 85748, Garching, Germany
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3
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Zhou J, Jia S, Hu X, Wang E, Xue X, Wu Y, Wang J, Dorn A, Ren X. Intermolecular Charge Transfer Induced Fragmentation of Formic Acid Dimers. PHYSICAL REVIEW LETTERS 2023; 130:233001. [PMID: 37354420 DOI: 10.1103/physrevlett.130.233001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 01/19/2023] [Accepted: 04/20/2023] [Indexed: 06/26/2023]
Abstract
We investigate the intermolecular nonradiative charge transfer process in a double hydrogen-bonded formic acid (FA) dimer, initiated by electron-collision induced double ionization of one FA molecule. Through fragment ions and electron coincident momentum measurements and ab initio calculations, we obtain direct evidence that electron transfer from the neighboring FA molecule to fill one of the two vacancies occurs by a potential energy curve crossing of FA^{++}+FA with FA^{+}+FA^{+*} curves, forming an electronic excited state of dicationic dimers. This process causes the breaking of two hydrogen bonds and subsequently the cleavage of C─H and C─O covalent bonds in the dimers, which is expected to be a general phenomenon occurring in molecular complexes and can have important implications for radiation damage to biological matter.
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Affiliation(s)
- Jiaqi Zhou
- School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Shaokui Jia
- School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Xiaoqing Hu
- Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
| | - Enliang Wang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Xiaorui Xue
- School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Yong Wu
- Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
| | - Jianguo Wang
- Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
| | - Alexander Dorn
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Xueguang Ren
- School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
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4
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Zhou J, Jia S, Skitnevskaya AD, Wang E, Hähnel T, Grigoricheva EK, Xue X, Li JX, Kuleff AI, Dorn A, Ren X. Concerted Double Hydrogen-Bond Breaking by Intermolecular Coulombic Decay in the Formic Acid Dimer. J Phys Chem Lett 2022; 13:4272-4279. [PMID: 35522820 DOI: 10.1021/acs.jpclett.2c00957] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Hydrogen bonds are ubiquitous in nature and of fundamental importance to the chemical and physical properties of molecular systems in the condensed phase. Nevertheless, our understanding of the structural and dynamical properties of hydrogen-bonded complexes in particular in electronic excited states remains very incomplete. Here, by using formic acid (FA) dimer as a prototype of DNA base pair, we investigate the ultrafast decay process initiated by removal of an electron from the inner-valence shell of the molecule upon electron-beam irradiation. Through fragment-ion and electron coincident momentum measurements and ab initio calculations, we find that de-excitation of an outer-valence electron at the same site can initiate ultrafast energy transfer to the neighboring molecule, which is in turn ionized through the emission of low-energy electrons. Our study reveals a concerted breaking of double hydrogen-bond in the dimer initiated by the ultrafast molecular rotations of two FA+ cations following this nonlocal decay mechanism.
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Affiliation(s)
- Jiaqi Zhou
- School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, Heidelberg 69117, Germany
| | - Shaokui Jia
- School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Anna D Skitnevskaya
- Laboratory of Quantum Chemistry, Irkutsk State University, Irkutsk 664003, Russia
- Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Heidelberg 69120, Germany
| | - Enliang Wang
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, Heidelberg 69117, Germany
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Theresa Hähnel
- Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Heidelberg 69120, Germany
| | - Emma K Grigoricheva
- Laboratory of Quantum Chemistry, Irkutsk State University, Irkutsk 664003, Russia
- Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Heidelberg 69120, Germany
| | - Xiaorui Xue
- School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Jian-Xing Li
- School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Alexander I Kuleff
- Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Heidelberg 69120, Germany
| | - Alexander Dorn
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, Heidelberg 69117, Germany
| | - Xueguang Ren
- School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, Heidelberg 69117, Germany
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5
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Zawadzki M, Luxford TFM, Kočišek J. Carboxylation Enhances Fragmentation of Furan upon Resonant Electron Attachment. J Phys Chem A 2020; 124:9427-9435. [PMID: 33125242 PMCID: PMC7667636 DOI: 10.1021/acs.jpca.0c07283] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 10/17/2020] [Indexed: 01/18/2023]
Abstract
We report a dissociative electron attachment study to 2-furoic acid (C5H4O3) isolated in a gas phase, which is a model molecule consisting of a carboxylic group and a furan ring. Dissociation of furan by low energy electrons is accessible only via electronic excited Feshbach resonances at energies of incident electrons above 5 eV. On the other hand, carboxylic acids are well-known to dissociate via attachment of electrons at subexcitation energies. Here we elucidate how the electron and proton transfer reactions induced by carboxylation influence stability of the furan ring. Overlap of the furan and carboxyl π orbitals results in transformation of the nondissociative π2 resonance of the furan ring to a dissociative resonance. The interpretation of hydrogen transfer reactions is supported by experimental studies of 3-methyl-2-furoic and 5-methyl-2-furoic acids (C6H6O3) and density functional theory (DFT) calculations.
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Affiliation(s)
- Mateusz Zawadzki
- J.
Heyrovský Institute of Physical Chemistry, Czech Academy of
Sciences, Dolejškova 3, 18223 Prague, Czech Republic
- Atomic
Physics Division, Department of Atomic, Molecular and Optical Physics,
Faculty of Applied Physics and Mathematics, Gdańsk University of Technology, ul. G. Narutowicza 11/12, 80-233 Gdańsk, Poland
| | - Thomas F. M. Luxford
- J.
Heyrovský Institute of Physical Chemistry, Czech Academy of
Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - Jaroslav Kočišek
- J.
Heyrovský Institute of Physical Chemistry, Czech Academy of
Sciences, Dolejškova 3, 18223 Prague, Czech Republic
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6
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Nag P, Čurík R, Tarana M, Polášek M, Ehara M, Sommerfeld T, Fedor J. Resonant states in cyanogen NCCN. Phys Chem Chem Phys 2020; 22:23141-23147. [PMID: 33025990 DOI: 10.1039/d0cp03333b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
In a combined experimental and theoretical study we probe the transient anion states (resonances) in cyanogen. Experimentally, we utilize electron energy loss spectroscopy which reveals the resonance positions by monitoring the excitation functions for vibrationally inelastic electron scattering. Four resonances are visible in the spectra, centered around 0.36 eV, 4.1, 5.3 and 7.3 eV. Theoretically, we explore the resonant states by using the regularized analytical continuation method. A very good agreement with the experiment is obtained for low-lying resonances, however, the computational method becomes unstable for higher-lying states. The lowest shape resonance (2Πu) is independently explored by the complex adsorbing potential method. In the experiment, this resonance is manifested by a pronounced boomerang structure. We show that the naive picture of viewing NCCN as a pseudodihalogen and focusing only on the CC stretch is invalid.
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Affiliation(s)
- Pamir Nag
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic.
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7
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Silva MO, Moreira GM, Bettega MHF, Sanchez SD. Electron and Positron Scattering by the Formamide Molecule. J Phys Chem A 2020; 124:6009-6015. [PMID: 32515965 DOI: 10.1021/acs.jpca.0c03779] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report calculated elastic integral, differential, and momentum transfer cross sections for electron and positron collisions with the formamide (HCONH2) molecule, for impact energies up to 10 eV. We have used the Schwinger multichannel method in the static-exchange and static-exchange plus polarization approximation for collisions of electrons and the static plus polarization approximation for collisions of positrons. The Born-closure procedure was applied to account for the long-range potential due to the permanent dipole moment of formamide. We obtained the well-characterized π* shape resonance located at around 2.38 eV, which belongs to the A″ symmetry of the Cs point group. Our integral and differential cross sections for collisions of electrons were compared with the data available in the literature and showed a good qualitative agreement. To the best of our knowledge, no experimental and theoretical data are currently available for positron-formamide collision, so our present cross sections were compared with the cross sections of formic acid, which is also polar and is isoeletronic to formamide.
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Affiliation(s)
- Murilo O Silva
- Departamento de Física, Universidade Federal do Paraná, Caixa Postal 19044, 81531-980 Curitiba, Paraná, Brazil
| | - Giseli M Moreira
- Departamento de Física, Universidade Federal do Paraná, Caixa Postal 19044, 81531-980 Curitiba, Paraná, Brazil
| | - Márcio H F Bettega
- Departamento de Física, Universidade Federal do Paraná, Caixa Postal 19044, 81531-980 Curitiba, Paraná, Brazil
| | - Sergio d'A Sanchez
- Departamento de Física, Universidade Federal do Paraná, Caixa Postal 19044, 81531-980 Curitiba, Paraná, Brazil
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8
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Slaughter DS, Weber T, Belkacem A, Trevisan CS, Lucchese RR, McCurdy CW, Rescigno TN. Selective bond-breaking in formic acid by dissociative electron attachment. Phys Chem Chem Phys 2020; 22:13893-13902. [PMID: 32542241 DOI: 10.1039/d0cp01522a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the results of a joint experimental and theoretical study of dissociative electron attachment to formic acid (HCOOH) in the 6-9 eV region, where H- fragment ions are a dominant product. Breaking of the C-H and O-H bonds is distinguished experimentally by deuteration of either site. We show that in this region H- ions can be produced by formation of two or possibly three Feshbach resonance (doubly-excited anion) states, one of which leads to either C-H or O-H bond scission, while the other can only produce formyloxyl radicals by O-H bond scission. Comparison of experimental and theoretical angular distributions of the anion fragment allows the elucidation of state specific pathways to dissociation.
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Affiliation(s)
- D S Slaughter
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
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9
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Ranković M, Kumar T P R, Nag P, Kočišek J, Fedor J. Temporary anions of the dielectric gas C 3F 7CN and their decay channels. J Chem Phys 2020; 152:244304. [PMID: 32610971 DOI: 10.1063/5.0008897] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We probe the transient anion states (resonances) in the dielectric gas C4F7N by the electron energy loss spectroscopy and the dissociative electron attachment spectroscopy. The vibrationally inelastic electron scattering leads to two excitation types. The first is the excitation of specific vibrational modes that are assigned with the help of an infrared spectrum of this molecule and quantum chemistry calculations. In the second type of vibrational excitation, the excess energy is randomized via internal vibrational redistribution in the temporary anion, and the electrons are emitted statistically. The electron attachment proceeds in three different regimes. The first is the formation of the parent C4F7N- anion at energies close to 0 eV. The second is a statistical evaporation of the F-atom, leading to the defluorinated anion C4F6N-. Finally, the third is dissociative electron attachment proceeding via the formation of several resonances and leading to a number of fragments. The present data explain the puzzling recent results of the pulsed-Townsend experiments with this gas.
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Affiliation(s)
- M Ranković
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - Ragesh Kumar T P
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - P Nag
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - J Kočišek
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - J Fedor
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
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10
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Ferreira da Silva F, do N Varella MT, Jones NC, Vrønning Hoffmann S, Denifl S, Bald I, Kopyra J. Electron-Induced Reactions in 3-Bromopyruvic Acid. Chemistry 2019; 25:5498-5506. [PMID: 30706547 DOI: 10.1002/chem.201806132] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/22/2019] [Indexed: 01/20/2023]
Abstract
3-Bromopyruvic acid (3BP) is a potential anti-cancer drug, the action of which on cellular metabolism is not yet entirely clear. The presence of a bromine atom suggests that it is also reactive towards low-energy electrons, which are produced in large quantities during tumour radiation therapy. Detailed knowledge of the interaction of 3BP with secondary electrons is a prerequisite to gain a complete picture of the effects of 3BP in different forms of cancer therapy. Herein, dissociative electron attachment (DEA) to 3BP in the gas phase has been studied both experimentally by using a crossed-beam setup and theoretically through scattering and quantum chemical calculations. These results are complemented by a vacuum ultraviolet absorption spectrum. The main fragmentation channel is the formation of Br- close to 0 eV and within several resonant features at 1.9 and 3-8 eV. At low electron energies, Br- formation proceeds through σ* and π* shape resonances, and at higher energies through core-excited resonances. It is found that the electron-capture cross-section is clearly increased compared with that of non-brominated pyruvic acid, but, at the same time, fragmentation reactions through DEA are significantly altered as well. The 3BP transient negative ion is subject to a lower number of fragmentation reactions than those of pyruvic acid, which indicates that 3BP could indeed act by modifying the electron-transport chains within oxidative phosphorylation. It could also act as a radio-sensitiser.
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Affiliation(s)
- Filipe Ferreira da Silva
- Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal
| | - Márcio T do N Varella
- Instituto de Física, Universidade de São Paulo, Rua do Matão 1371, 05508-090, São Paulo, Brazil
| | - Nykola C Jones
- ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000, Aarhus, Denmark
| | - Søren Vrønning Hoffmann
- ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000, Aarhus, Denmark
| | - Stephan Denifl
- Institut für Ionenphysik und Angewandte Physik and Center for Molecular Biosciences (CMBI), Leopold-Franzens Universität Innsbruck, Technikerstrasse 25, 6020, Innsbruck, Austria
| | - Ilko Bald
- Department of Chemistry-Physical Chemistry, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476, Potsdam-Golm, Germany
- Department 1-Analytical Chemistry and Reference Materials, BAM Federal Institute for Materials Research and Testing, Richard-Willstätter Strasse 11, 12489, Berlin, Germany
| | - Janina Kopyra
- Faculty of Sciences, Siedlce University, 3 Maja 54, 08-110, Siedlce, Poland
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11
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Zawadzki M, Ranković M, Kočišek J, Fedor J. Dissociative electron attachment and anion-induced dimerization in pyruvic acid. Phys Chem Chem Phys 2018; 20:6838-6844. [PMID: 29350234 DOI: 10.1039/c7cp07472g] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report partial cross sections for the dissociative electron attachment to pyruvic acid. A rich fragmentation dynamics is observed. Electronic structure calculations facilitate the identification of complex rearrangement reactions that occur during the dissociation. Furthermore, a number of fragment anions produced at electron energies close to 0 eV are observed, that cannot originate from single electron-molecule collisions. We ascribe their production to secondary reactions of the transient anions with neutral molecules. Such reactions turn out to be unusually efficient; the most probable reason for this is that they proceed via the formation of a double-hydrogen-bonded complex followed by an ultrafast proton transfer between the reaction partners.
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Affiliation(s)
- M Zawadzki
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague 8, Czech Republic.
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12
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Meneses G, Widmann C, Cunha T, Gil A, Ferreira da Silva F, Calhorda MJ, Limão-Vieira P. Unravelling the dissociation pathways of acetic acid upon electron transfer in potassium collisions: experimental and theoretical studies. Phys Chem Chem Phys 2018; 19:1083-1088. [PMID: 27942639 DOI: 10.1039/c6cp06375f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electron transfer in alkali-molecule collisions with gas phase acetic acid and its deuterated analogues resulting in OH- formation requires considerable internal rearrangement in the temporary negative ion. At a collision energy well above the threshold of negative ion formation, electron transfer from potassium to CH3COOH/CH3COOD and CD3COOH results not only in H transfer from CH3 to COOH/COOD, but also in H release from COOH and subsequent rearrangement to eliminate OH-. These processes are also investigated by theoretical post-Hartree-Fock and DFT calculations. The combination of both studies reveals that the most favourable intermediate mechanism occurs via diol formation. Such intramolecular H transfer is reported here for the first time in the context of electron transfer induced dissociation experiments in alkali-molecule collisions. A comprehensive fragmentation study is presented and dissociation mechanisms are suggested.
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Affiliation(s)
- G Meneses
- Laboratório de Colisões Atómicas e Moleculares, CEFITEC Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa Campus de Caparica, 2829-516 Caparica, Portugal.
| | - C Widmann
- Laboratório de Colisões Atómicas e Moleculares, CEFITEC Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa Campus de Caparica, 2829-516 Caparica, Portugal.
| | - T Cunha
- Laboratório de Colisões Atómicas e Moleculares, CEFITEC Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa Campus de Caparica, 2829-516 Caparica, Portugal.
| | - A Gil
- Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal.
| | - F Ferreira da Silva
- Laboratório de Colisões Atómicas e Moleculares, CEFITEC Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa Campus de Caparica, 2829-516 Caparica, Portugal.
| | - M J Calhorda
- Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal.
| | - P Limão-Vieira
- Laboratório de Colisões Atómicas e Moleculares, CEFITEC Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa Campus de Caparica, 2829-516 Caparica, Portugal.
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13
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Sala L, Szymańska IB, Dablemont C, Lafosse A, Amiaud L. Response under low-energy electron irradiation of a thin film of a potential copper precursor for focused electron beam induced deposition (FEBID). BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2018; 9:57-65. [PMID: 29379701 PMCID: PMC5769079 DOI: 10.3762/bjnano.9.8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 12/12/2017] [Indexed: 06/07/2023]
Abstract
Background: Focused electron beam induced deposition (FEBID) allows for the deposition of free standing material within nanometre sizes. The improvement of the technique needs a combination of new precursors and optimized irradiation strategies to achieve a controlled fragmentation of the precursor for leaving deposited material of desired composition. Here a new class of copper precursors is studied following an approach that probes some surface processes involved in the fragmentation of precursors. We use complexes of copper(II) with amines and perfluorinated carboxylate ligands that are solid and stable under ambient conditions. They are directly deposited on the surface for studying the fragmentation with surface science tools. Results: Infrared spectroscopy and high-resolution electron energy loss spectroscopy (HREELS) are combined to show that the precursor is able to spontaneously lose amine ligands under vacuum. This loss can be enhanced by mild heating. The combination of mass spectrometry and low-energy electron irradiation (0-15 eV) shows that full amine ligands can be released upon irradiation, and that fragmentation of the perfluorinated ligands is induced by electrons of energy as low as 1.5 eV. Finally, the cross section for this process is estimated from the temporal evolution in the experiments on electron-stimulated desorption (ESD). Conclusion: The release of full ligands under high vacuum and by electron irradiation, and the cross section measured here for ligands fragmentation allow one to envisage the use of the two precursors for FEBID studies.
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Affiliation(s)
- Leo Sala
- Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Univ Paris Sud, Université Paris-Saclay, F-91405 Orsay, France
| | - Iwona B Szymańska
- Department of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland
| | - Céline Dablemont
- Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Univ Paris Sud, Université Paris-Saclay, F-91405 Orsay, France
| | - Anne Lafosse
- Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Univ Paris Sud, Université Paris-Saclay, F-91405 Orsay, France
| | - Lionel Amiaud
- Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Univ Paris Sud, Université Paris-Saclay, F-91405 Orsay, France
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14
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Keolopile ZG, Ryder MR, Calzada B, Gutowski M, Buytendyk AM, Graham JD, Bowen KH. Electrophilicity of oxalic acid monomer is enhanced in the dimer by intermolecular proton transfer. Phys Chem Chem Phys 2017; 19:29760-29766. [PMID: 29105713 DOI: 10.1039/c7cp00474e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We have analyzed the effect of excess electron attachment on the network of hydrogen bonds in the oxalic acid dimer (OA)2. The most stable anionic structures may be viewed as complexes of a neutral hydrogenated moiety HOA˙ coordinated to an anionic deprotonated moiety (OA-H)-. HOA˙ acts as a double proton donor and (OA-H)- as a double proton acceptor. Thus the excess electron attachment drives intermolecular proton transfer. We have identified several cyclic hydrogen bonded structures of (OA)2-. Their stability has been analyzed in terms of the stability of the involved conformers, the energetic penalty for deformation of these conformers to the geometry of the dimer, and the two-body interaction energy between the deformed HOA˙ and (OA-H)-. There are at least seven isomers of (OA)2- with stabilization energies in the range of 1.26-1.39 eV. These energies are dominated by attractive two-body interaction energies. The anions are vertically bound electronically by 3.0-3.4 eV and adiabatically bound by at least 1.6 eV. The computational predictions are consistent with the anion photoelectron spectrum of (OA)2-. The spectrum consists of a broad feature, with an onset of 2.5 eV and spanning to 4.3 eV. The electron vertical detachment energy (VDE) is assigned to be 3.3 eV.
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Affiliation(s)
- Zibo G Keolopile
- Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, Scotland EH14 4AS, UK.
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15
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Houdoux D, Houplin J, Amiaud L, Lafosse A, Dablemont C. Interfacial water on organic substrates at cryogenic temperatures: hydrogen bonding and quantification in the submonolayer regime. Phys Chem Chem Phys 2017; 19:2304-2312. [PMID: 28054680 DOI: 10.1039/c6cp03328h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Water molecules were used to probe the physical and chemical properties of a model hydrophilic organic organized layer. To this end, H2O adsorption on mercaptoundecanoic acid self-assembled monolayers (SAMs) was investigated at the molecular level under ultra-high vacuum by high resolution electron energy loss spectroscopy (HREELS), through the sensitivity of the water OH stretching modes to the molecular environment. The water interfacial layer formation and structure were studied upon deposition at 28 K. A direct sensitive quantification in the submonolayer regime (10-80% of completion) was achieved by the sole measurement of the OH stretching mode frequencies, and the dominant basic (-COO-)/acidic (-COOH) forms of the terminal functions could be probed. The surface densities of the water interfacial layer and the SAM terminal functions were measured independently, and demonstrated to be comparable. This means that the SAM terminal functions provided anchors for water adsorption through two hydrogen bonds and that the SAM acted as a template even at 28 K. Upon annealing at 110 K, the water molecules were observed to form clusters of higher molecular density, dewetting the supporting substrate. Finally, the vanishing of the supporting substrate vibrational signature, due to the masking effect by the deposited water layer, was used to estimate the depth probed by HREELS through water layers to be 11 ± 2 Å.
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Affiliation(s)
- D Houdoux
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Univ. Paris Sud, Université Paris Saclay, F-91405 Orsay, France.
| | - J Houplin
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Univ. Paris Sud, Université Paris Saclay, F-91405 Orsay, France.
| | - L Amiaud
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Univ. Paris Sud, Université Paris Saclay, F-91405 Orsay, France.
| | - A Lafosse
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Univ. Paris Sud, Université Paris Saclay, F-91405 Orsay, France.
| | - C Dablemont
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Univ. Paris Sud, Université Paris Saclay, F-91405 Orsay, France.
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16
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Davis D, Sajeev Y. Low energy electron catalyst: the electronic origin of catalytic strategies. Phys Chem Chem Phys 2016; 18:27715-27720. [PMID: 27711601 DOI: 10.1039/c6cp05480c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using a low energy electron (LEE) as a catalyst, the electronic origin of the catalytic strategies corresponding to substrate selectivity, reaction specificity and reaction rate enhancement is investigated for a reversible unimolecular elementary reaction. An electronic energy complementarity between the catalyst and the substrate molecule is the origin of substrate selectivity and reaction specificity. The electronic energy complementarity is induced by tuning the electronic energy of the catalyst. The energy complementarity maximizes the binding forces between the catalyst and the molecule. Consequently, a new electronically metastable high-energy reactant state and a corresponding new low barrier reaction path are resonantly created for a specific reaction of the substrate through the formation of a catalyst-substrate transient adduct. The LEE catalysis also reveals a fundamental structure-energy correspondence in the formation of the catalyst-substrate transient adduct. Since the energy complementarities corresponding to the substrate molecules of the forward and the backward steps of the reversible reactions are not the same due to their structural differences, the LEE catalyst exhibits a unique one-way catalytic strategy, i.e., the LEE catalyst favors the reversible reaction more effectively in one direction. A characteristic stronger binding of the catalyst to the transition state of the reaction than in the initial reactant state and the final product state is the molecular origin of barrier lowering.
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Affiliation(s)
- Daly Davis
- Laser Diagnostic Group, Institute for Plasma Research, Gandhinagar 382428, India
| | - Y Sajeev
- Theoretical Chemistry Section, Bhabha Atomic Research Centre, Mumbai 400085, India.
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17
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Keolopile ZG, Gutowski M, Buonaugurio A, Collins E, Zhang X, Erb J, Lectka T, Bowen KH, Allan M. Importance of Time Scale and Local Environment in Electron-Driven Proton Transfer. The Anion of Acetoacetic Acid. J Am Chem Soc 2015; 137:14329-40. [DOI: 10.1021/jacs.5b08134] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Zibo G. Keolopile
- Department
of Physics, University of Botswana, Private Bag 0022, Gaborone, Botswana
- Institute
of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Maciej Gutowski
- Institute
of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Angela Buonaugurio
- Department
of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Evan Collins
- Department
of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Xinxing Zhang
- Department
of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Jeremy Erb
- Department
of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Thomas Lectka
- Department
of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Kit H. Bowen
- Department
of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Michael Allan
- Department
of Chemistry, University of Fribourg, chemin du Musée 9, Fribourg 1700, Switzerland
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18
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Buonaugurio A, Graham J, Buytendyk A, Bowen KH, Ryder MR, Keolopile ZG, Haranczyk M, Gutowski M. Communication: Remarkable electrophilicity of the oxalic acid monomer: An anion photoelectron spectroscopy and theoretical study. J Chem Phys 2014; 140:221103. [DOI: 10.1063/1.4882655] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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19
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Janečková R, Kubala D, May O, Fedor J, Allan M. Experimental evidence on the mechanism of dissociative electron attachment to formic acid. PHYSICAL REVIEW LETTERS 2013; 111:213201. [PMID: 24313485 DOI: 10.1103/physrevlett.111.213201] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Indexed: 06/02/2023]
Abstract
Two mechanisms for dissociative electron attachment in HCOOH, the formation of HCOO(-)+H, were proposed in the literature: (i) via a direct electron attachment into a σ* resonance, augmented by dipole binding of the incident electron [G. A. Gallup et al., Phys. Rev. A 79, 042701 (2009)], and (ii) with the 1.8 eV π* resonance as a doorway state, linked to the products by symmetry lowering-distortion of the temporary anion, primarily the C-H bond, from the planar symmetry [T. N. Rescigno et al., Phys. Rev. Lett. 96, 213201 (2006)]. The later mechanism implies a reduction of the cross section upon deuteration of the hydrogen bonded to the C atom, whereas the former mechanism would leave the cross section unaffected. Our experimental absolute cross sections for the four isotopomers of formic acid show that deuteration on the C atom reduces the cross section value only marginally (by 12%) compared to deuteration on the O atom (reduction by a factor of 16), and thus favor mechanism (i).
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Affiliation(s)
- R Janečková
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700 Fribourg, Switzerland
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20
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Analytical continuation in coupling constant method; application to the calculation of resonance energies and widths for organic molecules: Glycine, alanine and valine and dimer of formic acid. Chem Phys 2013. [DOI: 10.1016/j.chemphys.2013.03.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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21
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Houplin J, Amiaud L, Humblot V, Martin I, Matar E, Azria R, Pradier CM, Lafosse A. Selective terminal function modification of SAMs driven by low-energy electrons (0-15 eV). Phys Chem Chem Phys 2013; 15:7220-7. [PMID: 23558312 DOI: 10.1039/c3cp43750g] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Low-energy electron induced degradation of a model self-assembled monolayer (SAM) of acid terminated alkanethiol was studied under ultra-high vacuum (UHV) conditions at room and low (~40 K) temperatures. Low-energy electron induced chemical modifications of 11-mercaptoundecanoic acid (MUA, HS-(CH2)10-COOH) SAMs deposited on gold were probed in situ as a function of the irradiation energy (<11 eV) by combining two complementary techniques: High Resolution Electron Energy Loss Spectroscopy (HREELS), a surface sensitive vibrational spectroscopy technique, and Electron Stimulated Desorption (ESD) analysis of neutral fragments. The SAM's terminal functions were observed to be selectively damaged at around 1 eV by a resonant electron attachment mechanism, observed to decay by CO, CO2 and H2O formation and desorption. CO2 and H2O were also directly identified at low temperature by vibrational analysis of the irradiated SAMs. At higher irradiation energy, both terminal functions and spacer alkyl chains are damaged upon electron irradiation, by resonant and non-resonant processes.
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Affiliation(s)
- J Houplin
- Université Paris-Sud, Institut des Sciences Moléculaires d'Orsay (ISMO), UMR 8214, Orsay, France
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22
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Freitas TC, Coutinho K, Varella MTDN, Lima MAP, Canuto S, Bettega MHF. Electron collisions with the HCOOH⋯(H2O)n complexes (n = 1, 2) in liquid phase: The influence of microsolvation on the π* resonance of formic acid. J Chem Phys 2013; 138:174307. [DOI: 10.1063/1.4803119] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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23
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Michaud M, Bazin M, Sanche L. Absolute cross sections for vibrational excitations of cytosine by low energy electron impact. J Chem Phys 2012; 137:115103. [PMID: 22998289 PMCID: PMC3812122 DOI: 10.1063/1.4752655] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The absolute cross sections (CSs) for vibrational excitations of cytosine by electron impact between 0.5 and 18 eV were measured by electron-energy loss (EEL) spectroscopy of the molecule deposited at monolayer coverage on an inert Ar substrate. The vibrational energies compare to those that have been reported from IR spectroscopy of cytosine isolated in Ar matrix, IR and Raman spectra of polycrystalline cytosine, and ab initio calculation. The CSs for the various H bending modes at 142 and 160 meV are both rising from their energy threshold up to 1.7 and 2.1 × 10(-17) cm(2) at about 4 eV, respectively, and then decrease moderately while maintaining some intensity at 18 eV. The latter trend is displayed as well for the CS assigned to the NH(2) scissor along with bending of all H at 179 meV. This overall behavior in electron-molecule collision is attributed to direct processes such as the dipole, quadrupole, and polarization contributions, etc. of the interaction of the incident electron with a molecule. The CSs for the ring deformation at 61 meV, the ring deformation with N-H symmetric wag at 77 meV, and the ring deformations with symmetric bending of all H at 119 meV exhibit common enhancement maxima at 1.5, 3.5, and 5.5 eV followed by a broad hump at about 12 eV, which are superimposed on the contribution due to the direct processes. At 3.5 eV, the CS values for the 61-, 77-, and 119-meV modes reach 4.0, 3.0, and 4.5 × 10(-17) cm(2), respectively. The CS for the C-C and C-O stretches at 202 meV, which dominates in the intermediate EEL region, rises sharply until 1.5 eV, reaches its maximum of 5.7 × 10(-17) cm(2) at 3.5 eV and then decreases toward 18 eV. The present vibrational enhancements, correspond to the features found around 1.5 and 4.5 eV in electron transmission spectroscopy (ETS) and those lying within 1.5-2.1 eV, 5.2-6.8 eV, and 9.5-10.9 eV range in dissociative electron attachment (DEA) experiments with cytosine in gas phase. While the ETS features are ascribed to shape resonances associated with the electron occupation of the second and third antibonding π-orbitals of the molecule in its ground state, the correspondence with DEA features suggests the existence of common precursor anion states decaying with certain probabilities into the vibrationally excited ground state.
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Affiliation(s)
- M Michaud
- Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine et Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada.
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24
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Gerardi HK, DeBlase AF, Leavitt CM, Su X, Jordan KD, McCoy AB, Johnson MA. Structural characterization of electron-induced proton transfer in the formic acid dimer anion, (HCOOH)2−, with vibrational and photoelectron spectroscopies. J Chem Phys 2012; 136:134318. [DOI: 10.1063/1.3693271] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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25
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d'A Sanchez S, Lima MAP, Varella MTDN. Multimode vibrational couplings in resonant positron annihilation. PHYSICAL REVIEW LETTERS 2011; 107:103201. [PMID: 21981501 DOI: 10.1103/physrevlett.107.103201] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Indexed: 05/31/2023]
Abstract
The mechanisms for multimode vibrational couplings in resonant positron annihilation are not well understood. We show that these resonances can arise from positron-induced distortions of the potential energy surface (target response to the positron field). Though these distortions can transfer energy into single- and multiquantum vibrations, they have so far been disregarded as a pathway to resonant annihilation. We also compare the existing annihilation theories and show that the currently accepted model can be cast as a special case of the Feshbach annihilation theory.
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Affiliation(s)
- Sergio d'A Sanchez
- Departamento de Física, Universidade Federal do Paraná, CP 19044, 81531-090 Curitiba, PR, Brazil
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26
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Homem MGP, Iga I, Sugohara RT, Sanches IP, Lee MT. Role of adsorption effects on absolute electron-molecule cross-section calibration using the relative flow technique. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:013109. [PMID: 21280818 DOI: 10.1063/1.3525799] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this work, we report an experimental investigation on relative flow-rate determination for vapors. The mechanism of adsorption-desorption of vapors on surfaces is considered. In contrast to previous investigations, our study shows that the adsorption of vapors on surfaces may significantly affect the flow-rate determination and consequently the measured cross sections. Particularly, for water, it can result in an overestimation of 35% in the cross sections.
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Affiliation(s)
- M G P Homem
- Departamento de Física, UFSC, Florianópolis/SC, Brazil.
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27
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Silva FFD, Denifl S, Märk TD, Doltsinis NL, Ellis AM, Scheier P. Electron Attachment to Formamide Clusters in Helium Nanodroplets. J Phys Chem A 2010; 114:1633-8. [DOI: 10.1021/jp909890h] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- F. Ferreira da Silva
- Institut für Ionenphysik und Angewandte Physik and Center of Molecular Biosciences Innsbruck, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria, Department of Physics, King’s College London, The Strand, London WC2R 2LS, United Kingdom, and Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| | - S. Denifl
- Institut für Ionenphysik und Angewandte Physik and Center of Molecular Biosciences Innsbruck, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria, Department of Physics, King’s College London, The Strand, London WC2R 2LS, United Kingdom, and Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| | - T. D. Märk
- Institut für Ionenphysik und Angewandte Physik and Center of Molecular Biosciences Innsbruck, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria, Department of Physics, King’s College London, The Strand, London WC2R 2LS, United Kingdom, and Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| | - N. L. Doltsinis
- Institut für Ionenphysik und Angewandte Physik and Center of Molecular Biosciences Innsbruck, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria, Department of Physics, King’s College London, The Strand, London WC2R 2LS, United Kingdom, and Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| | - A. M. Ellis
- Institut für Ionenphysik und Angewandte Physik and Center of Molecular Biosciences Innsbruck, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria, Department of Physics, King’s College London, The Strand, London WC2R 2LS, United Kingdom, and Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| | - P. Scheier
- Institut für Ionenphysik und Angewandte Physik and Center of Molecular Biosciences Innsbruck, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria, Department of Physics, King’s College London, The Strand, London WC2R 2LS, United Kingdom, and Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
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28
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Brooks PR. Electron transfer collisions with oriented trifluoroacetic acid (CF3CO2H). J Phys Chem A 2009; 113:14296-301. [PMID: 20028156 DOI: 10.1021/jp9029369] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Electron transfer collisions between neutral K atoms and neutral, oriented trifluoroacetic acid molecules, CF(3)CO(2)H, are studied in crossed molecular beams at center of mass energies from 6 to 18 eV. An electron transfer produces a pair of ions with enough energy to escape the Coulomb attraction, and the ions are detected in separate time-of-flight mass spectrometers. The principle ions formed are K(+) and the trifluoroacetate ion, CF(3)CO(2)(-) ion, and this channel is favored for attack at the positive (-CO(2)H) end of the molecule. The steric asymmetry suggests that the electron is transferred into the pi*(CO) orbital. The nascent K(+) perturbs the molecular symmetry, allowing electron migration to the sigma*(OH) orbital to break the O-H bond and form CF(3)CO(2)(-).
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Affiliation(s)
- Philip R Brooks
- Chemistry Department and Rice Quantum Institute, Rice University Houston, Texas 77005, USA.
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29
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Brooks PR. Experimental evidence for the role of the pi(CO)* orbital in electron transfer to gas phase acetic acid CH3CO2H: effects of molecular orientation. J Chem Phys 2009; 130:151102. [PMID: 19388728 DOI: 10.1063/1.3122902] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Electron transfer from K atoms to oriented acetic acid molecules produces acetate ions (and K(+)) when the CO(2)H end of the molecule is attacked. The electron enters the pi(CO)(*) orbital and the donor atom distorts the molecule to allow migration to the sigma(OH)(*) orbital, thereby breaking the bond.
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Affiliation(s)
- Philip R Brooks
- Department of Chemistry and Rice Quantum Institute, Rice University, Houston, Texas 77251, USA.
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30
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Stable Valence Anions of Nucleic Acid Bases and DNA Strand Breaks Induced by Low Energy Electrons. CHALLENGES AND ADVANCES IN COMPUTATIONAL CHEMISTRY AND PHYSICS 2008. [DOI: 10.1007/978-1-4020-8184-2_21] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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