1
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Abstract
We present a comparison of the photoionization dynamics of the 4d shell of XeF2 from threshold to 250 eV to those of the prototypical 4d shell of atomic Xe. The new experimental data include spin-orbit and ligand-field-resolved partial cross sections, photoelectron angular distributions, branching fractions, and lifetime widths for the 4d-hole states. The spin-orbit branching fractions and angular distributions are remarkably similar to the corresponding distributions from atomic Xe across a broad energy interval that includes both the intense shape resonance in the f continuum and a Cooper minimum in the same channel. The angular distributions and branching fractions are also in reasonably good agreement with our first-principles theoretical calculations on XeF2. Data are also presented on the lifetime widths of the substate-resolved 4d-hole states of XeF2. While the trends in the widths are similar to those in the earlier experimental and theoretical work, the linewidths are considerably smaller than in the previous measurements, which may require some reinterpretation of the decay mechanism. Finally, we present new data and an analysis of the Auger electron spectra for ionization above the 4d thresholds and resonant Auger spectra for several pre-edge features.
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Affiliation(s)
- R Forbes
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - P Hockett
- National Research Council of Canada, 100 Sussex Dr., Ottawa, Ontario K1A 0R6, Canada
| | - I Powis
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - J D Bozek
- Synchrotron SOLEIL, l'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France
| | - D M P Holland
- Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, United Kingdom
| | - S T Pratt
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
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2
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Patanen M, Abid AR, Pratt ST, Kivimäki A, Trofimov AB, Skitnevskaya AD, Grigoricheva EK, Gromov EV, Powis I, Holland DMP. Valence shell photoelectron angular distributions and vibrationally resolved spectra of imidazole: A combined experimental-theoretical study. J Chem Phys 2021; 155:054304. [PMID: 34364329 DOI: 10.1063/5.0058983] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Linearly polarized synchrotron radiation has been used to record polarization dependent valence shell photoelectron spectra of imidazole in the photon energy range 21-100 eV. These have allowed the photoelectron angular distributions, as characterized by the anisotropy parameter β, and the electronic state intensity branching ratios to be determined. Complementing these experimental data, theoretical photoionization partial cross sections and β-parameters have been calculated for the outer valence shell orbitals. The assignment of the structure appearing in the experimental photoelectron spectra has been guided by vertical ionization energies and spectral intensities calculated by various theoretical methods that incorporate electron correlation and orbital relaxation. Strong orbital relaxation effects have been found for the 15a', nitrogen lone-pair orbital. The calculations also predict that configuration mixing leads to the formation of several low-lying satellite states. The vibrational structure associated with ionization out of a particular orbital has been simulated within the Franck-Condon model using harmonic vibrational modes. The adiabatic approximation appears to be valid for the X 2A″ state, with the β-parameter for this state being independent of the level of vibrational excitation. However, for all the other outer valence ionic states, a disparity occurs between the observed and the simulated vibrational structure, and the measured β-parameters are at variance with the behavior expected at the level of the Franck-Condon approximation. These inconsistencies suggest that the excited electronic states may be interacting vibronically such that the nuclear dynamics occur over coupled potential energy surfaces.
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Affiliation(s)
- M Patanen
- Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, P. O. Box 3000, 90014 Oulu, Finland
| | - A R Abid
- Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, P. O. Box 3000, 90014 Oulu, Finland
| | - S T Pratt
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - A Kivimäki
- Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, P. O. Box 3000, 90014 Oulu, Finland
| | - A B Trofimov
- Laboratory of Quantum Chemical Modeling of Molecular Systems, Irkutsk State University, Karl Marx Str. 1, 664003 Irkutsk, Russia
| | - A D Skitnevskaya
- Laboratory of Quantum Chemical Modeling of Molecular Systems, Irkutsk State University, Karl Marx Str. 1, 664003 Irkutsk, Russia
| | - E K Grigoricheva
- Laboratory of Quantum Chemical Modeling of Molecular Systems, Irkutsk State University, Karl Marx Str. 1, 664003 Irkutsk, Russia
| | - E V Gromov
- Laboratory of Quantum Chemical Modeling of Molecular Systems, Irkutsk State University, Karl Marx Str. 1, 664003 Irkutsk, Russia
| | - I Powis
- School of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - D M P Holland
- Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, United Kingdom
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3
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Abstract
Single-photon, photoelectron-photoion coincidence spectroscopy is used to record the mass-selected ion spectra and slow photoelectron spectra of C4H5 radicals produced by the abstraction of hydrogen atoms from three C4H6 precursors by fluorine atoms generated by a microwave discharge. Three different C4H5 isomers are identified, with the relative abundances depending on the nature of the precursor (1-butyne, 1,2-butadiene, and 1,3-butadiene). The results are compared with our previous work using 2-butyne as a precursor [Hrodmarsson, H. R. J. Phys. Chem. A 2019, 123, 1521-1528]. The slow photoelectron spectra provide new information on the three radical isomers that is in good agreement with previous experimental and theoretical results [Lang, M. J. Phys. Chem. A 2015, 119, 3995-4000; Hansen, N. J. Phys. Chem. A 2006, 110, 3670-3678]. The energy scans of the C4H5 photoionization signal are recorded with substantially better resolution and signal-to-noise ratio than those in earlier work, allowing the observation of autoionizing resonances based on excited states of the C4H5 cation. Photoelectron images recorded at several energies are also reported, providing insight into the decay processes of these excited states. Finally, in contrast to the earlier work using 2-butyne as a precursor, where H-atom abstraction was the only observed process, F- and H-atom additions to the present precursors are also observed through the detection of C4H6F, C4H5F, and C4H7.
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Affiliation(s)
- S Hartweg
- Synchrotron Soleil, L'Orme des Merisiers, Gif-sur-Yvette F-91192, France
| | - J-C Loison
- Institut des Sciences Moléculaires (ISM), CNRS, Univ. Bordeaux, 351 cours de la Libération, Talence 33400, France
| | - S Boyé-Péronne
- Institut des Sciences Moléculaires d'Orsay, CNRS, Université Paris-Saclay, Orsay F-91405, France
| | - B Gans
- Institut des Sciences Moléculaires d'Orsay, CNRS, Université Paris-Saclay, Orsay F-91405, France
| | - D M P Holland
- STFC, Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, U.K
| | - G A Garcia
- Synchrotron Soleil, L'Orme des Merisiers, Gif-sur-Yvette F-91192, France
| | - L Nahon
- Synchrotron Soleil, L'Orme des Merisiers, Gif-sur-Yvette F-91192, France
| | - S T Pratt
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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4
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Harper OJ, Hassenfratz M, Loison JC, Garcia GA, de Oliveira N, Hrodmarsson HR, Pratt ST, Boyé-Péronne S, Gans B. Erratum: “Quantifying the photoionization cross section of the hydroxyl radical” [J. Chem. Phys. 150, 141103 (2019)]. J Chem Phys 2020; 152:189903. [DOI: 10.1063/5.0010934] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- O. J. Harper
- Institut des Sciences Moléculaires D’Orsay (ISMO), UMR 8214 CNRS, Université Paris-Sud, Université Paris-Saclay, F-91405 Orsay Cedex, France
| | - M. Hassenfratz
- Institut des Sciences Moléculaires D’Orsay (ISMO), UMR 8214 CNRS, Université Paris-Sud, Université Paris-Saclay, F-91405 Orsay Cedex, France
| | - J.-C. Loison
- Institut des Sciences Moléculaires, UMR 5255 CNRS-Université de Bordeaux, Bât.A12, 351 Cours de la Libération, F-33405 Talence Cedex, France
| | - G. A. Garcia
- Synchrotron SOLEIL, L’Orme des merisiers, Saint Aubin BP48, F-91192 Gif sur Yvette Cedex, France
| | - N. de Oliveira
- Synchrotron SOLEIL, L’Orme des merisiers, Saint Aubin BP48, F-91192 Gif sur Yvette Cedex, France
| | - H. R. Hrodmarsson
- Synchrotron SOLEIL, L’Orme des merisiers, Saint Aubin BP48, F-91192 Gif sur Yvette Cedex, France
| | - S. T. Pratt
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - S. Boyé-Péronne
- Institut des Sciences Moléculaires D’Orsay (ISMO), UMR 8214 CNRS, Université Paris-Sud, Université Paris-Saclay, F-91405 Orsay Cedex, France
| | - B. Gans
- Institut des Sciences Moléculaires D’Orsay (ISMO), UMR 8214 CNRS, Université Paris-Sud, Université Paris-Saclay, F-91405 Orsay Cedex, France
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5
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Trofimov AB, Belogolova AM, Serebrennikova SA, Forbes R, Pratt ST, Holland DMP. An experimental and theoretical study of the C 1s ionization satellites in CH 3I. J Chem Phys 2019; 150:224303. [PMID: 31202236 DOI: 10.1063/1.5099699] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The C 1s ionization spectrum of CH3I has been studied both experimentally and theoretically. Synchrotron radiation has been employed to record polarization dependent photoelectron spectra at a photon energy of 614 eV. These spectra encompass the main-line due to the C 1s single-hole state and the peaks associated with the shake-up satellites. Vertical ionization energies and relative photoelectron intensities have been computed using the fourth-order algebraic-diagrammatic construction approximation scheme for the one-particle Green's function and the 6-311++G** basis set. The theoretical spectrum derived from these calculations agrees qualitatively with the experimental results, thereby allowing the principal spectral features to be assigned. According to our calculations, two 2A1 shake-up states of the C 1s-1 σCI → σCI * type with singlet and triplet intermediate coupling of the electron spins (S' = 0, 1) play an important role in the spectrum and contribute significantly to the overall intensity. Both of these states are expected to have dissociative diabatic potential energy surfaces with respect to the C-I separation. Whereas the upper of these states perturbs the manifold of Rydberg states, the lower state forms a band which is characterized by a strongly increased width. Our results indicate that the lowest shake-up peak with significant spectral intensity is due to the pair (S' = 0, 1) of 2E (C 1s-1 I 5p → σCI *) states. We predict that these 2E states acquire photoelectron intensity due to spin-orbit interaction. Such interactions play an important role here due to the involvement of the I 5p orbitals.
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Affiliation(s)
- A B Trofimov
- Laboratory of Quantum Chemistry, Irkutsk State University, Karl Marx Str. 1, 664003 Irkutsk, Russia
| | - A M Belogolova
- Laboratory of Quantum Chemistry, Irkutsk State University, Karl Marx Str. 1, 664003 Irkutsk, Russia
| | - S A Serebrennikova
- Laboratory of Quantum Chemistry, Irkutsk State University, Karl Marx Str. 1, 664003 Irkutsk, Russia
| | - R Forbes
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - S T Pratt
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - D M P Holland
- Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, United Kingdom
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6
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Harper OJ, Hassenfratz M, Loison JC, Garcia GA, de Oliveira N, Hrodmarsson H, Pratt ST, Boyé-Péronne S, Gans B. Quantifying the photoionization cross section of the hydroxyl radical. J Chem Phys 2019; 150:141103. [DOI: 10.1063/1.5091966] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- O. J. Harper
- Institut des Sciences Moléculaires d’Orsay (ISMO), UMR 8214 CNRS, Université Paris-Sud, Université Paris-Saclay, F-91405 Orsay Cedex, France
| | - M. Hassenfratz
- Institut des Sciences Moléculaires d’Orsay (ISMO), UMR 8214 CNRS, Université Paris-Sud, Université Paris-Saclay, F-91405 Orsay Cedex, France
| | - J.-C. Loison
- Institut des Sciences Moléculaires, UMR 5255 CNRS–Université de Bordeaux, Bât.A12, 351 cours de la Libération, F-33405 Talence Cedex, France
| | - G. A. Garcia
- Synchrotron SOLEIL, L’Orme des merisiers, Saint Aubin BP48, F-91192 Gif sur Yvette Cedex, France
| | - N. de Oliveira
- Synchrotron SOLEIL, L’Orme des merisiers, Saint Aubin BP48, F-91192 Gif sur Yvette Cedex, France
| | - H.R. Hrodmarsson
- Synchrotron SOLEIL, L’Orme des merisiers, Saint Aubin BP48, F-91192 Gif sur Yvette Cedex, France
| | - S. T. Pratt
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - S. Boyé-Péronne
- Institut des Sciences Moléculaires d’Orsay (ISMO), UMR 8214 CNRS, Université Paris-Sud, Université Paris-Saclay, F-91405 Orsay Cedex, France
| | - B. Gans
- Institut des Sciences Moléculaires d’Orsay (ISMO), UMR 8214 CNRS, Université Paris-Sud, Université Paris-Saclay, F-91405 Orsay Cedex, France
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7
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Hrodmarsson HR, Loison JC, Jacovella U, Holland DMP, Boyé-Péronne S, Gans B, Garcia GA, Nahon L, Pratt ST. Valence-Shell Photoionization of C4H5: The 2-Butyn-1-yl Radical. J Phys Chem A 2019; 123:1521-1528. [DOI: 10.1021/acs.jpca.8b11809] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- H. R. Hrodmarsson
- Synchrotron Soleil, L’Orme des Merisiers, F-91192 Gif-sur-Yvette, France
| | - J.-C. Loison
- Institut des Sciences Moléculaires, Université Bordeaux, 33400 Talence, France
| | - U. Jacovella
- Laboratorium für Physikalische Chemie, ETH Zürich, 8093 Zürich, Switzerland
| | - D. M. P. Holland
- STFC, Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, United Kingdom
| | - S. Boyé-Péronne
- Institut des Sciences Moléculaires d’Orsay, UMR 8214, CNRS & Univ. Paris-Sud & Université Paris-Saclay, F-91405 Orsay, France
| | - B. Gans
- Institut des Sciences Moléculaires d’Orsay, UMR 8214, CNRS & Univ. Paris-Sud & Université Paris-Saclay, F-91405 Orsay, France
| | - G. A. Garcia
- Synchrotron Soleil, L’Orme des Merisiers, F-91192 Gif-sur-Yvette, France
| | - L. Nahon
- Synchrotron Soleil, L’Orme des Merisiers, F-91192 Gif-sur-Yvette, France
| | - S. T. Pratt
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439 United States
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8
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Affiliation(s)
- Ananya Sen
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL, USA
| | - S. T. Pratt
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL, USA
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9
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Xie M, Shen Z, Pratt ST, Lee YP. Vibrational autoionization of state-selective jet-cooled methanethiol (CH 3SH) investigated with infrared + vacuum-ultraviolet photoionization. Phys Chem Chem Phys 2018; 19:29153-29161. [PMID: 29085925 DOI: 10.1039/c7cp06433k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Vibrational autoionization of Rydberg states provides key information about nonadiabatic processes above an ionization threshold. We employed time-of-flight mass detection of CH3SH+ to record vibrational-state selective photo-ionization efficiency (PIE) spectra of jet-cooled methanethiol (CH3SH) on exciting CH3SH to a specific vibrationally excited state with an infrared (IR) laser, followed by excitation with a tunable laser in the vacuum-ultraviolet (VUV) region for ionization. Autoionizing Rydberg states assigned to the ns, np, nd and nf series are identified. When IR light at 2601 (ν3, SH stretching mode) and 2948 cm-1 (ν2, CH3 symmetric stretching mode) was employed, the Rydberg series converged to the respective vibrationally excited (ν3 and ν2) states of CH3SH+. When IR light at 3014 cm-1 (overlapped ν1/ν9, CH3 antisymmetric stretching and CH2 antisymmetric stretching modes) was employed, Rydberg series converging to two vibrationally excited states (ν1 and ν9) of CH3SH+ were observed. When IR light at 2867 cm-1 (2ν10, overtone of CH3 deformation mode) and 2892 cm-1 (2ν4, overtone of CH2 scissoring mode) was employed, both Δν = -1 and Δν = -2 ionization transitions were observed; there is evidence for direct ionization from the initial state into the CH3SH+ (ν4+ = 1) continuum. In all observed IR-VUV-PIE spectra, the ns and nd series show intensity greater than the other Rydberg series, which is consistent with the fact that the highest-occupied molecular orbital of CH3SH is a p-like lone pair orbital on the S atom. The quantum yields for autoionization of various vibrational excited states are discussed. Values of ν1 = 3035, ν2 = 2884, ν3 = 2514, and ν9 = 2936 cm-1 for CH3SH+ derived from the converged limits agree satisfactorily with values observed for Ar-tagged CH3SH+ at 3026, 2879, 2502, and 2933 cm-1.
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Affiliation(s)
- Min Xie
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan.
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10
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Chartrand AM, McCormack EF, Jacovella U, Holland DMP, Gans B, Tang X, Garcia GA, Nahon L, Pratt ST. Photoelectron angular distributions from rotationally resolved autoionizing states of N2. J Chem Phys 2017; 147:224303. [DOI: 10.1063/1.5004538] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Affiliation(s)
- A. M. Chartrand
- Department of Physics, Bryn Mawr College, Bryn Mawr, Pennsylvania 19010, USA
| | - E. F. McCormack
- Department of Physics, Bryn Mawr College, Bryn Mawr, Pennsylvania 19010, USA
| | - U. Jacovella
- Laboratorium für Physikalische Chemie, ETH Zürich, 8093 Zürich, Switzerland
| | - D. M. P. Holland
- STFC, Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, United Kingdom
| | - B. Gans
- Institut des Sciences Moléculaires d’Orsay (ISMO), UMR 8214 CNRS, Univ. Paris-Sud, Université Paris-Saclay, F-91405 Orsay, France
| | - Xiaofeng Tang
- Synchrotron Soleil, L’Orme des Merisiers, F-91192 Gif-sur-Yvette, France
| | - G. A. Garcia
- Synchrotron Soleil, L’Orme des Merisiers, F-91192 Gif-sur-Yvette, France
| | - L. Nahon
- Synchrotron Soleil, L’Orme des Merisiers, F-91192 Gif-sur-Yvette, France
| | - S. T. Pratt
- Argonne National Laboratory, Argonne, Illinois 60439, USA
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11
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Affiliation(s)
- Ananya Sen
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - S. T. Pratt
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - K. L. Reid
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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12
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Picón A, Lehmann CS, Bostedt C, Rudenko A, Marinelli A, Osipov T, Rolles D, Berrah N, Bomme C, Bucher M, Doumy G, Erk B, Ferguson KR, Gorkhover T, Ho PJ, Kanter EP, Krässig B, Krzywinski J, Lutman AA, March AM, Moonshiram D, Ray D, Young L, Pratt ST, Southworth SH. Hetero-site-specific X-ray pump-probe spectroscopy for femtosecond intramolecular dynamics. Nat Commun 2016; 7:11652. [PMID: 27212390 PMCID: PMC4879250 DOI: 10.1038/ncomms11652] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 04/18/2016] [Indexed: 11/09/2022] Open
Abstract
New capabilities at X-ray free-electron laser facilities allow the generation of two-colour femtosecond X-ray pulses, opening the possibility of performing ultrafast studies of X-ray-induced phenomena. Particularly, the experimental realization of hetero-site-specific X-ray-pump/X-ray-probe spectroscopy is of special interest, in which an X-ray pump pulse is absorbed at one site within a molecule and an X-ray probe pulse follows the X-ray-induced dynamics at another site within the same molecule. Here we show experimental evidence of a hetero-site pump-probe signal. By using two-colour 10-fs X-ray pulses, we are able to observe the femtosecond time dependence for the formation of F ions during the fragmentation of XeF2 molecules following X-ray absorption at the Xe site.
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Affiliation(s)
- A. Picón
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - C. S. Lehmann
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - C. Bostedt
- Argonne National Laboratory, Argonne, Illinois 60439, USA
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA
| | - A. Rudenko
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - A. Marinelli
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - T. Osipov
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - D. Rolles
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
- Deutsches Elektronen-Synchrotron (DESY), Hamburg 22607, Germany
| | - N. Berrah
- Department of Physics, University of Connecticut, Storrs, Connecticut 06269, USA
| | - C. Bomme
- Deutsches Elektronen-Synchrotron (DESY), Hamburg 22607, Germany
| | - M. Bucher
- Argonne National Laboratory, Argonne, Illinois 60439, USA
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - G. Doumy
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - B. Erk
- Deutsches Elektronen-Synchrotron (DESY), Hamburg 22607, Germany
| | - K. R. Ferguson
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - T. Gorkhover
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - P. J. Ho
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - E. P. Kanter
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - B. Krässig
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - J. Krzywinski
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - A. A. Lutman
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - A. M. March
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - D. Moonshiram
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - D. Ray
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - L. Young
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - S. T. Pratt
- Argonne National Laboratory, Argonne, Illinois 60439, USA
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13
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Jacovella U, Holland DMP, Boyé-Péronne S, Gans B, de Oliveira N, Ito K, Joyeux D, Archer LE, Lucchese RR, Xu H, Pratt ST. A Near-Threshold Shape Resonance in the Valence-Shell Photoabsorption of Linear Alkynes. J Phys Chem A 2015; 119:12339-48. [DOI: 10.1021/acs.jpca.5b06949] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- U. Jacovella
- Laboratorium
für Physikalische Chemie, ETH Zürich, 8093 Zürich, Switzerland
| | - D. M. P. Holland
- STFC, Daresbury
Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, U.K
| | - S. Boyé-Péronne
- Institut des Sciences Moléculaires d’Orsay, UMR 8214, CNRS & Univ. Paris-Sud, F-91405 Orsay, France
| | - Bérenger Gans
- Institut des Sciences Moléculaires d’Orsay, UMR 8214, CNRS & Univ. Paris-Sud, F-91405 Orsay, France
| | - N. de Oliveira
- Synchrotron Soleil,
L’Orme des Merisiers, F-91192 Gif-sur-Yvette, France
| | - K. Ito
- Synchrotron Soleil,
L’Orme des Merisiers, F-91192 Gif-sur-Yvette, France
| | - D. Joyeux
- Synchrotron Soleil,
L’Orme des Merisiers, F-91192 Gif-sur-Yvette, France
| | - L. E. Archer
- Synchrotron Soleil,
L’Orme des Merisiers, F-91192 Gif-sur-Yvette, France
| | - R. R. Lucchese
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Hong Xu
- Argonne National
Laboratory, Argonne, Illinois 60439, United States
| | - S. T. Pratt
- Argonne National
Laboratory, Argonne, Illinois 60439, United States
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Jacovella U, Holland DMP, Boyé-Péronne S, Gans B, de Oliveira N, Joyeux D, Archer LE, Lucchese RR, Xu H, Pratt ST. High-resolution vacuum-ultraviolet photoabsorption spectra of 1-butyne and 2-butyne. J Chem Phys 2015. [DOI: 10.1063/1.4926541] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- U. Jacovella
- Laboratorium für Physikalische Chemie, ETH Zürich, 8093 Zürich, Switzerland
| | - D. M. P. Holland
- STFC, Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, United Kingdom
| | - S. Boyé-Péronne
- Institut des Sciences Moléculaires d’Orsay, UMR 8214, CNRS and Université Paris-Sud, F-91405 Orsay, France
| | - B. Gans
- Institut des Sciences Moléculaires d’Orsay, UMR 8214, CNRS and Université Paris-Sud, F-91405 Orsay, France
| | - N. de Oliveira
- Synchrotron Soleil, L’Orme des Merisiers, F-91192 Gif-sur-Yvette, France
| | - D. Joyeux
- Synchrotron Soleil, L’Orme des Merisiers, F-91192 Gif-sur-Yvette, France
| | - L. E. Archer
- Synchrotron Soleil, L’Orme des Merisiers, F-91192 Gif-sur-Yvette, France
| | - R. R. Lucchese
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA
| | - H. Xu
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - S. T. Pratt
- Argonne National Laboratory, Argonne, Illinois 60439, USA
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Abstract
We have determined the I (2)P3/2 and (2)P1/2 branching fractions following the photodissociation of methyl iodide (CH3I) via a number of vibronic bands associated with the B̃ ((2)E3/2)6s Rydberg state at excitation wavelengths between 201.2 and 192.7 nm. Vacuum ultraviolet light at 118.2 nm was used to ionize both the product iodine atoms and the methyl radical cofragments, and velocity map ion imaging was used to determine the product translational energy distributions and angular distributions. The known relative photoionization cross sections for I (2)P3/2 and (2)P1/2 at 118.2 nm were used to determine the corresponding branching fractions. The results extend our earlier work at 193 nm by Xu et al. (J. Chem. Phys. 2013, 139, 214310), and complement the closely related work of González et al. (J. Chem. Phys. 2011, 135, 021102). We find that for most of the excited vibronic levels of the B̃ state studied, the I (2)P3/2 branching ratio is small, but nonzero, and that this channel is associated with internally excited CH3 radicals. The results are discussed in relation to the recent theoretical results of Alekseyev et al. (J. Chem. Phys. 2011, 134, 044303).
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Affiliation(s)
- Hong Xu
- Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - S T Pratt
- Argonne National Laboratory, Argonne, Illinois 60439, United States
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Jacovella U, Holland DMP, Boyé-Péronne S, Joyeux D, Archer LE, de Oliveira N, Nahon L, Lucchese RR, Xu H, Pratt ST. High-resolution photoabsorption spectrum of jet-cooled propyne. J Chem Phys 2014; 141:114303. [DOI: 10.1063/1.4894853] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- U. Jacovella
- Laboratorium für Physikalische Chemie, ETH Zürich, 8093 Zürich, Switzerland
| | - D. M. P. Holland
- STFC, Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, United Kingdom
| | - S. Boyé-Péronne
- Institut des Sciences Moléculaires d’Orsay, UMR 8214, CNRS & Univ. Paris-Sud, F-91405 Orsay, France
| | - D. Joyeux
- Synchrotron Soleil, L’Orme des Merisiers, F-91192 Gif-sur-Yvette, France
| | - L. E. Archer
- Synchrotron Soleil, L’Orme des Merisiers, F-91192 Gif-sur-Yvette, France
| | - N. de Oliveira
- Synchrotron Soleil, L’Orme des Merisiers, F-91192 Gif-sur-Yvette, France
| | - L. Nahon
- Synchrotron Soleil, L’Orme des Merisiers, F-91192 Gif-sur-Yvette, France
| | - R. R. Lucchese
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA
| | - Hong Xu
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - S. T. Pratt
- Argonne National Laboratory, Argonne, Illinois 60439, USA
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Affiliation(s)
- Hong Xu
- Argonne National Laboratory,
Argonne, Illinois 60439, United States
| | - S. T. Pratt
- Argonne National Laboratory,
Argonne, Illinois 60439, United States
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Affiliation(s)
- Hong Xu
- Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - S. T. Pratt
- Argonne National Laboratory, Argonne, Illinois 60439, United States
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Jungen C, Jungen M, Pratt ST. The Jahn-Teller effect in the 3pe' Rydberg state of H3: review of experimental and ab initio determinations. Philos Trans A Math Phys Eng Sci 2012; 370:5074-5087. [PMID: 23028155 DOI: 10.1098/rsta.2012.0103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The dissociative recombination (DR) of H(3)(+) ions with electrons, producing neutral atomic and molecular fragments, is driven primarily by the vibronic Jahn-Teller (JT) interaction between the electronic components of the pe' e(-)-H(3)(+) collision (Rydberg) channel. The JT parameters characterizing this interaction are therefore of great interest as they are required for the theoretical predictions of the DR cross section. In this contribution, we review various determinations of these quantities that have been made previously, based both on spectroscopic studies of 3pe' Rydberg-excited H(3) states, and on the analysis of the corresponding ab initio H(3) Rydberg potential surfaces near the conical intersection (D(3h) symmetry) for n=3-5. The highly correlated theoretical 3pe' potential surfaces of Mistrík et al. are used for a new determination of both the linear and quadratic JT terms.
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Affiliation(s)
- Ch Jungen
- Laboratoire Aimé Cotton du CNRS, Bâtiment 505, Université de Paris-Sud, 91405 Orsay, France.
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Xu H, Jacovella U, Ruscic B, Pratt ST, Lucchese RR. Near-threshold shape resonance in the photoionization of 2-butyne. J Chem Phys 2012; 136:154303. [DOI: 10.1063/1.3701762] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Thiré N, Cireasa R, Staedter D, Blanchet V, Pratt ST. Time-resolved predissociation of the vibrationless level of the B state of CH3I. Phys Chem Chem Phys 2011; 13:18485-96. [DOI: 10.1039/c1cp22057h] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Fang L, Hoener M, Gessner O, Tarantelli F, Pratt ST, Kornilov O, Buth C, Gühr M, Kanter EP, Bostedt C, Bozek JD, Bucksbaum PH, Chen M, Coffee R, Cryan J, Glownia M, Kukk E, Leone SR, Berrah N. Double core-hole production in N2: beating the Auger clock. Phys Rev Lett 2010; 105:083005. [PMID: 20868097 DOI: 10.1103/physrevlett.105.083005] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Indexed: 05/29/2023]
Abstract
We investigate the creation of double K-shell holes in N2 molecules via sequential absorption of two photons on a time scale shorter than the core-hole lifetime by using intense x-ray pulses from the Linac Coherent Light Source free electron laser. The production and decay of these states is characterized by photoelectron spectroscopy and Auger electron spectroscopy. In molecules, two types of double core holes are expected, the first with two core holes on the same N atom, and the second with one core hole on each N atom. We report the first direct observations of the former type of core hole in a molecule, in good agreement with theory, and provide an experimental upper bound for the relative contribution of the latter type.
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Affiliation(s)
- L Fang
- Physics Department, Western Michigan University, Kalamazoo, Michigan 49008, USA.
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Young L, Kanter EP, Krässig B, Li Y, March AM, Pratt ST, Santra R, Southworth SH, Rohringer N, Dimauro LF, Doumy G, Roedig CA, Berrah N, Fang L, Hoener M, Bucksbaum PH, Cryan JP, Ghimire S, Glownia JM, Reis DA, Bozek JD, Bostedt C, Messerschmidt M. Femtosecond electronic response of atoms to ultra-intense X-rays. Nature 2010; 466:56-61. [PMID: 20596013 DOI: 10.1038/nature09177] [Citation(s) in RCA: 259] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Accepted: 05/10/2010] [Indexed: 11/09/2022]
Abstract
An era of exploring the interactions of high-intensity, hard X-rays with matter has begun with the start-up of a hard-X-ray free-electron laser, the Linac Coherent Light Source (LCLS). Understanding how electrons in matter respond to ultra-intense X-ray radiation is essential for all applications. Here we reveal the nature of the electronic response in a free atom to unprecedented high-intensity, short-wavelength, high-fluence radiation (respectively 10(18) W cm(-2), 1.5-0.6 nm, approximately 10(5) X-ray photons per A(2)). At this fluence, the neon target inevitably changes during the course of a single femtosecond-duration X-ray pulse-by sequentially ejecting electrons-to produce fully-stripped neon through absorption of six photons. Rapid photoejection of inner-shell electrons produces 'hollow' atoms and an intensity-induced X-ray transparency. Such transparency, due to the presence of inner-shell vacancies, can be induced in all atomic, molecular and condensed matter systems at high intensity. Quantitative comparison with theory allows us to extract LCLS fluence and pulse duration. Our successful modelling of X-ray/atom interactions using a straightforward rate equation approach augurs favourably for extension to complex systems.
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Affiliation(s)
- L Young
- Argonne National Laboratory, Argonne, Illinois 60439, USA.
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Hoener M, Fang L, Kornilov O, Gessner O, Pratt ST, Gühr M, Kanter EP, Blaga C, Bostedt C, Bozek JD, Bucksbaum PH, Buth C, Chen M, Coffee R, Cryan J, Dimauro L, Glownia M, Hosler E, Kukk E, Leone SR, McFarland B, Messerschmidt M, Murphy B, Petrovic V, Rolles D, Berrah N. Ultraintense x-ray induced ionization, dissociation, and frustrated absorption in molecular nitrogen. Phys Rev Lett 2010; 104:253002. [PMID: 20867372 DOI: 10.1103/physrevlett.104.253002] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Indexed: 05/11/2023]
Abstract
Sequential multiple photoionization of the prototypical molecule N2 is studied with femtosecond time resolution using the Linac Coherent Light Source (LCLS). A detailed picture of intense x-ray induced ionization and dissociation dynamics is revealed, including a molecular mechanism of frustrated absorption that suppresses the formation of high charge states at short pulse durations. The inverse scaling of the average target charge state with x-ray peak brightness has possible implications for single-pulse imaging applications.
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Affiliation(s)
- M Hoener
- Western Michigan University Physics Department, Kalamazoo, Michigan 49008, USA
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Abstract
A simple analytical approach is presented to describe the dissociative recombination (DR) of an electron with H3+ and its isotopomers. The principal assumption is that resonant capture mediated by the Jahn-Teller interaction dominates the cross section. The only input required comes from spectroscopic data on the 3pE;{'} Rydberg state of H3 and the nu_{2} vibrational frequencies of H3+ and its isotopomers. The approach provides an independent prediction of the low-energy DR cross sections and rates, and is in good agreement with the latest experimental and theoretical determinations.
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Affiliation(s)
- Ch Jungen
- Laboratoire Aimé Cotton du CNRS, Bâtiment 505, Université de Paris-Sud F91405 Orsay, France
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31
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Abstract
Vibrational autoionization induced by the Renner-Teller interaction in linear polyatomic molecules is considered in the context of the three-state electrostatic model developed by Gauyacq and Jungen [Mol. Phys. 41, 383 (1980)]. For small interactions, simple formulas are derived for the quantum defect matrix elements and the autoionization rates in terms of the more common Renner-Teller parameters derived from spectroscopic analyses of low-lying Rydberg states. These formulas should provide guidance for empirical fitting of quantum defect parameters to spectra of high Rydberg states. Consideration of typical values of the Renner-Teller parameters also allows the estimation of vibrational autoionization rates induced by these interactions. These estimates support the validity of the Deltav=-1 propensity rule for vibrational autoionization. Constraints on the vibrational autoionization rates for the symmetric stretching vibration are also discussed. In the following paper, electron capture by polyatomic molecular ions into vibrationally autoionizing Rydberg states is considered from the same perspective, and a simple formula is derived to allow the estimation of the effect of this process on dissociative recombination cross sections.
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Affiliation(s)
- Ch Jungen
- Laboratoire Aime Cotton du CNRS, Universite de Paris-Sud, 91405 Orsay, France
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Abstract
The combination of ion-imaging and vacuum-ultraviolet (vuv) single-photon ionization is used to study the internal energy dependence of the relative photoionization yields of the C(2)H(5),n-C(3)H(7), and i-C(3)H(7) radicals following the 266 nm photodissociation of the corresponding alkyl iodides. The comparison of the ion images obtained by vuv photoionization of the radical with those obtained by two-photon-resonant, three-photon ionization of the complementary I (2)P(32) and I*(2)P(12) atoms allows the extraction of the internal energy dependence of the cross sections. Factors influencing the appearance of the ion images in the different detection channels are discussed, including the secondary fragmentation of the neutral radicals, Franck-Condon factors for the photoionization process, and the unimolecular fragmentation of the parent photoions.
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Affiliation(s)
- Haiyan Fan
- Argonne National Laboratory, Argonne, IL 60439, USA
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Abstract
The photodissociation of allyl iodide (C3H5I) at 193 nm was investigated by using a combination of vacuum-ultraviolet photoionization of the allyl radical, resonant multiphoton ionization of the iodine atoms, and velocity map imaging. The data provide insight into the primary C-I bond fission process and into the dissociative ionization of the allyl radical to produce C3H3+. The experimental results are consistent with the earlier results of Szpunar et al. [J. Chem. Phys. 119, 5078 (2003)], in that some allyl radicals with internal energies higher than the secondary dissociation barrier are found to be stable. This stability results from the partitioning of available energy between the rotational and vibrational degrees of freedom of the radical, the effects of a centrifugal barrier along the reaction coordinate, and the effects of the kinetic shift in the secondary dissociation of the allyl radical. The present results suggest that the primary dissociation of allyl iodide to allyl radicals plus I*(2P(1/2)) is more important than previously suspected.
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Affiliation(s)
- H Fan
- Argonne National Laboratory, Argonne, Illinois 60439, USA
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Abstract
Two methods based on vacuum ultraviolet (vuv) photoionization are presented for the determination of the spin-orbit branching fractions of the halogen atom produced in the photodissociation of halogenated hydrocarbons. Both methods make use of differences in the photoionization cross sections of the 2P(3/2) ground state and the 2P(1/2) excited-state of the neutral halogen atom. In the first approach, measurements of the total photoionization signal of the halogen atom are made at several vuv wavelengths, and the difference in the wavelength dependences for the 2P(3/2) and 2P(1/2) atoms allows the extraction of the branching fractions. In the second approach, the vuv wavelength is set close to the ionization threshold of the 2P(3/2) atom (well above that of the 2P(1/2) atom), and measurements are made at several electric field strengths, which shift the ionization threshold and thus vary the photoionization cross sections. In both methods, the relative cross sections of the ground- and excited-state atoms are determined by using the known branching fractions for the 266 nm photodissociation of methyl iodide. These methods are applied to the photodissociation of isopropyl iodide and allyl iodide, two systems for which standard ion-imaging techniques do not provide unique branching fractions.
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Affiliation(s)
- H Fan
- Argonne National Laboratory, Argonne, Illinois 60439, USA
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Abstract
Velocity map imaging was used to study the 193 nm photodissociation of propargyl bromide C(3)H(3)Br as well as the photoionization dynamics of the resulting propargyl radical C(3)H(3). Images were recorded by using single-photon vacuum ultraviolet ionization of the propargyl radical and by using two-photon resonant, three-photon ionization of the ground state Br((2)P(32)) and spin-orbit excited Br(*)((2)P(12)) atoms. Analysis of these data allowed the determination of the branching ratio Br:Br(*) as well as the photofragment angular distributions. Images of C(3)H(3) produced by the photodissociation of both C(3)H(3)Br and C(3)H(3)Cl were recorded at several energies between 8.97 and 9.12 eV, as well as at 9.86 eV, and showed no obvious internal energy dependence of the relative photoionization cross sections.
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Affiliation(s)
- H Fan
- Argonne National Laboratory, Argonne, Illinois 60439, USA
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Abstract
A combination of ion imaging and vacuum ultraviolet, single-photon ionization is used to study the internal energy dependence of the photoionization cross section of isopropyl radicals produced by the 266 nm photodissociation of isopropyl iodide. The isopropyl radicals so produced have internal energies of approximately 0.3-2.0 eV. Images recorded for photoionization energies from just below the adiabatic ionization threshold at 7.37+/-0.02 and 8.04 eV are essentially identical both to each other and to that recorded at 9.67 eV. These results imply that the photoionization cross section is only weakly dependent on internal energy. Several factors contributing to this observation are discussed, as are the implications for the photoionization of other systems with significant internal excitation.
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Affiliation(s)
- H Fan
- Argonne National Laboratory, Argonne, Illinois 60439, USA
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Abstract
Vibrationally hot CH(3) and CF(3) were produced by the 266 nm photodissociation of CH(3)I and CF(3)I, respectively, and probed by single-photon ionization at 118 nm. Comparison of the ion images of the CH(3) and CF(3) fragments with those of the complementary I atoms, and with previous measurements of the product branching fractions, allowed the determination of the relative photoion yields as a function of the vibrational energy of the molecular radical. Some general ideas about the internal-energy dependence of photoionization cross sections are also discussed.
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Affiliation(s)
- F Aguirre
- Argonne National Laboratory, Argonne, Illinois 60439, USA
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Abstract
▪ Abstract The vibrationally autoionizing Rydberg states of small polyatomic molecules provide a fascinating laboratory in which to study fundamental nonadiabatic processes. In this review, recent results on the vibrational mode dependence of vibrational autoionization are discussed. In general, autoionization rates depend strongly on the character of the normal mode driving the process and on the electronic character of the Rydberg electron. Although quantitative calculations based on multichannel quantum defect theory are available for some polyatomic molecules, including H3, only qualitative information exists for most molecules. This review shows how qualitative information, such as Walsh diagrams along different normal coordinates of the molecule, can provide insight into the vibrational autoionization rates.
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Affiliation(s)
- S T Pratt
- Argonne National Laboratory, Argonne, Illinois 60439 USA.
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Abstract
The photoionization and photodissociation dynamics of H(2) and D(2) in selected rovibrational levels of the B (1)Sigma(u) (+) and C (1)Pi(u) states have been investigated by velocity map ion imaging. The selected rotational levels of the B (1)Sigma(u) (+) and C (1)Pi(u) states are prepared by three-photon excitation from the ground state. The absorption of fourth photon results in photoionization to produce H(2)(+) X (2)Sigma(g)(+) or photodissociation to produce a ground-state H(1s) atom and an excited H atom with n >or= 2. The H(2) (+) ion can be photodissociated by absorption of a fifth photon. The resulting H(+) or D(+) ion images provide information on the vibrational state dependence of the photodissociation angular distribution of the molecular ion. The excited H(n >or= 2) atoms produced by the neutral dissociation process can also be ionized by the absorption of a fifth photon. The resulting ion images provide insight into the excited state branching ratios and angular distributions of the neutral photodissociation process. While the experimental ion images contain information on both the ionic and neutral processes, these can be separated based on constraints imposed on the fragment translational energies. The angular distribution of the rings in the ion images indicates that the neutral dissociation of molecular hydrogen and its isotopes is quite complex, and involves coupling to both doubly excited electronic states and the dissociation continua of singly excited Rydberg states.
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Affiliation(s)
- F Aguirre
- Argonne National Laboratory, Argonne, Illinois 60439, USA
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Affiliation(s)
- Patrice Bell
- Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, and Department of Chemistry, Purdue University, West Lafayette, Indiana 47907
| | - F. Aguirre
- Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, and Department of Chemistry, Purdue University, West Lafayette, Indiana 47907
| | - E. R. Grant
- Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, and Department of Chemistry, Purdue University, West Lafayette, Indiana 47907
| | - S. T. Pratt
- Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, and Department of Chemistry, Purdue University, West Lafayette, Indiana 47907
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Abstract
Double-resonance laser excitation and high-resolution energy dispersive photoelectron spectroscopy were used to determine the ionic rotational-state distributions following vibrational autoionization of Rydberg states of water having principal quantum number n=8-10 and converging to the X (2)B(1) (1,0,0) state of H(2)O(+). Where possible, these states were identified by comparison with results of a calculation based on multichannel quantum defect theory. Symmetry and angular momentum constraints link the observed ionic rotational states to particular values of the orbital angular momentum of the Rydberg electron, l, and to the partial-wave composition of the ejected electron. In particular, this connection allows an unambiguous determination of the even or odd character of the partial waves and provides a test of the predicted character of the autoionizing resonances. The effects of l mixing induced by the nonspherical nature of the ionic field are plainly evident in the ion distributions. The present results also allow a tentative assignment of some resonances to the previously unidentified np Rydberg states.
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Affiliation(s)
- W L Glab
- Department of Physics, Texas Tech University, Lubbock, Texas 79409, USA
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Bell P, Aguirre F, Grant ER, Pratt ST. Mode dependent vibrational autoionization of Rydberg states of NO2. II. Comparing the symmetric stretching and bending vibrations. J Chem Phys 2004; 120:2667-76. [PMID: 15268410 DOI: 10.1063/1.1638379] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Triple-resonance excitation and high-resolution photoelectron spectroscopy are combined to characterize the mode selectivity of vibrational autoionization of the high Rydberg states of NO2. Photoelectron spectra and vibrational branching fractions are reported for autoionizing Rydberg states converging to the NO2+ X 1Sigmag +(110) state, that is, with one quantum in the symmetric stretch, nu1, and one quantum in the bending vibration, nu2. These results indicate that autoionization proceeds most efficiently through the loss of one quantum from the symmetric stretch rather than from the bending vibration. The implications of this result are discussed in terms of the autoionization mechanism.
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Affiliation(s)
- Patrice Bell
- Argonne National Laboratory, Argonne, Illinois 60439, USA
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Aguirre F, Pratt ST. Velocity map imaging of the photodissociation of CF3I: Vibrational energy dependence of the recoil anisotropy. J Chem Phys 2003. [DOI: 10.1063/1.1530582] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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Dehmer PM, Pratt ST, Dehmer JL. Photoelectron spectra of xenon dimer (Xe2*) obtained by resonantly enhanced multiphoton ionization. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100294a029] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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