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Liu Q, Li Z, Liu P, Yang X, Yu S. Resonance-state selective photodissociation dynamics of OCS + hv → CS(X1Σ+) + O(3Pj=2,1,0) via the 21Σ+ state. J Chem Phys 2023; 158:2888161. [PMID: 37139996 DOI: 10.1063/5.0150850] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 04/21/2023] [Indexed: 05/05/2023] Open
Abstract
Understanding vacuum ultraviolet photodissociation dynamics of Carbonyl sulfide (OCS) is of considerable importance in the study of atmospheric chemistry. Yet, photodissociation dynamics of the CS(X1Σ+) + O(3Pj=2,1,0) channels following excitation to the 21Σ+(ν1',1,0) state has not been clearly understood so far. Here, we investigate the O(3Pj=2,1,0) elimination dissociation processes in the resonance-state selective photodissociation of OCS between 147.24 and 156.48 nm by using the time-sliced velocity-mapped ion imaging technique. The total kinetic energy release spectra are found to exhibit highly structured profiles, indicative of the formation of a broad range of vibrational states of CS(1Σ+). The fitted CS(1Σ+) vibrational state distributions differ for the three 3Pj spin-orbit states, but a general trend of the inverted characteristics is observed. Additionally, the wavelength-dependent behaviors are also observed in the vibrational populations for CS(1Σ+, v). The CS(X1Σ+, v = 0) has a significantly strong population at several shorter wavelengths, and the most populated CS(X1Σ+, v) is gradually transferred to a higher vibrational state with the decrease in the photolysis wavelength. The measured overall β-values for the three 3Pj spin-orbit channels slightly increase and then abruptly decrease as the photolysis wavelength increases, while the vibrational dependences of β-values show an irregularly decreasing trend with increasing CS(1Σ+) vibrational excitation at all studied photolysis wavelengths. The comparison of the experimental observations for this titled channel and the S(3Pj) channel reveals that two different intersystem crossing mechanisms may be involved in the formation of the CS(X1Σ+) + O(3Pj=2,1,0) photoproducts via the 21Σ+ state.
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Affiliation(s)
- Qian Liu
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang Province, People's Republic of China
| | - Zheng Li
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang Province, People's Republic of China
| | - Peng Liu
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang Province, People's Republic of China
| | - Xueming Yang
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang Province, People's Republic of China
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, People's Republic of China
- Department of Chemistry, College of Science, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
| | - Shengrui Yu
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang Province, People's Republic of China
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Li Z, Liao H, Yang W, Yang X, Yu S. Vacuum ultraviolet photodissociation of OCS via the 2 1Σ + state: the S( 1D 2) elimination channel. Phys Chem Chem Phys 2022; 24:17870-17878. [PMID: 35851633 DOI: 10.1039/d2cp02044k] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photodissociation of OCS is necessary to model the primary photochemical processes of OCS in the global cycling of sulfur and interstellar photochemistry. Here, by combining the time-sliced velocity-map ion imaging technique with the single vacuum ultraviolet photon ionization method, we have studied the CO(1Σ+, v) + S(1D2) photoproduct channel from the OCS photodissociation via the eight different vibrational resonances ( = 1-8) in the 21Σ+(, 1, 0) ← X1Σ+(0, 0, 0) band. From the measured S(1D2) images, the wavelength-dependent CO(1Σ+, v) vibrational state populations have been obtained in the wavelength range of 142.98-154.37 nm. The majority of the CO(1Σ+, v) photoproducts are shown to abruptly populate from low vibrational states to high vibrational states as the photolysis wavelength decreases from 152.38 to 148.92 nm. The anisotropy parameters (β) for the CO(1Σ+, v) + S(1D2) channel have also been determined from the images of the S(1D2) photoproducts. It is found that the vibrational state-specific β-values present a similar decreasing trend with increasing CO vibrational excitation for all the eight vibrational resonances of OCS*(21Σ+). These observations indicate that there is a possibility that more than one non-adiabatic dissociation pathways with different dissociation lifetimes are involved in the formation of CO(1Σ+) + S(1D2) photoproducts from the initial vibronic levels of the 21Σ+ state to the final dissociative state.
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Affiliation(s)
- Zheng Li
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou, 311231, Zhejiang Province, P. R. China.
| | - Hong Liao
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou, 311231, Zhejiang Province, P. R. China.
| | - Wenshao Yang
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou, 311231, Zhejiang Province, P. R. China.
| | - Xueming Yang
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou, 311231, Zhejiang Province, P. R. China. .,State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, Liaoning Province, P. R. China.,Department of Chemistry, College of Science, Southern University of Science and Technology, 1088 Xueyuan Road, Shenzhen, 518055, P. R. China
| | - Shengrui Yu
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou, 311231, Zhejiang Province, P. R. China.
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Ling C, Liao H, Yuan D, Chen W, Tan Y, Li W, Yu S, Yang X, Wang X. Vacuum ultraviolet photodissociation dynamics of OCS + hv → CO( 1Σ +) + S( 1S 0) via the E and F Rydberg states. Phys Chem Chem Phys 2021; 23:5809-5816. [PMID: 33684186 DOI: 10.1039/d1cp00078k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The state-resolved photodissociation of the CO(1Σ+) + S(1S0) photoproduct channel, formed by vacuum ultraviolet photoexcitation of OCS to a progression of the symmetric stretching vibration (ν1') in the E and F states, has been investigated by using the time-sliced velocity map ion imaging technique. The total kinetic energy release spectra and the vibrational state specific anisotropy parameters (β) were obtained based on the raw images of S(1S0) photoproducts detected in the wavelength ranges of 134.40-140.98 nm, respectively. Except for vibrational band origins, the CO(1Σ+) photoproducts are found to have more significant populations at highly vibrationally excited states as the symmetric stretching vibrational excitation of the E and F states increases. Furthermore, the vibrational-state specific β values for the CO(1Σ+) + S(1S0) channel via the E and F states both show a sudden change from negative to positive in the vicinity of moderately vibronic levels of the E and F states. This anomalous phenomenon suggests that multiple excited states with different symmetries are involved in the photoexcitation process at relatively short photolysis wavelengths due to the strong vibronic couplings existing in the higher vibronic levels of the E and F states, and the formation of CO(1Σ+) + S(1S0) photoproducts may proceed by different nonadiabatic interactions from the prepared excited states to the lower dissociative state 1Σ+, with strong dependence of the initially symmetric stretching excitation in the Rydberg-type transitions.
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Affiliation(s)
- Caining Ling
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China.
| | - Hong Liao
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China.
| | - Daofu Yuan
- Center for Advanced Chemical Physics and Department of Chemical Physics, School of Chemistry and Materials Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei 230026, Anhui, P. R. China.
| | - Wentao Chen
- Center for Advanced Chemical Physics and Department of Chemical Physics, School of Chemistry and Materials Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei 230026, Anhui, P. R. China.
| | - Yuxin Tan
- Center for Advanced Chemical Physics and Department of Chemical Physics, School of Chemistry and Materials Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei 230026, Anhui, P. R. China.
| | - Wantao Li
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China.
| | - Shengrui Yu
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China.
| | - Xueming Yang
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China. and State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, Liaoning, P. R. China
| | - Xingan Wang
- Center for Advanced Chemical Physics and Department of Chemical Physics, School of Chemistry and Materials Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei 230026, Anhui, P. R. China.
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Xu F, Tan YX, Yuan DF, Chen WT, Yu SR, Xie T, Wang T, Yang XM, Wang XA. Wavelength dependent photodissociation of OCS via F 31Π Rydberg state: CO(X1Σ+)+S(1D2) product channel. CHINESE J CHEM PHYS 2020. [DOI: 10.1063/1674-0068/cjcp2008147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Fei Xu
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
| | - Yu-xin Tan
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
| | - Dao-fu Yuan
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
| | - Wen-tao Chen
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
| | - Sheng-rui Yu
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, Hangzhou 311231, China
| | - Ting Xie
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
| | - Tao Wang
- State key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- College of Science, Sothern University of Science and Technology, Shenzhen 518055, China
| | - Xue-ming Yang
- State key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- College of Science, Sothern University of Science and Technology, Shenzhen 518055, China
| | - Xing-an Wang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
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5
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Wang SW, Yuan DF, Chen WT, Tang L, Yu SR, Yang XM, Wang XA. Photodissociation dynamics of OCS near 128 nm: S(3PJ=2,1,0), S(1D2) and S(1S0) channels. CHINESE J CHEM PHYS 2020. [DOI: 10.1063/1674-0068/cjcp1911179] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Si-wen Wang
- Hefei National Laboratory for Materials Science at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Dao-fu Yuan
- Hefei National Laboratory for Materials Science at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Wen-tao Chen
- Hefei National Laboratory for Materials Science at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Ling Tang
- Hefei National Laboratory for Materials Science at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Sheng-rui Yu
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, Hangzhou 311231, China
| | - Xue-ming Yang
- State key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- School of Science, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xing-an Wang
- Hefei National Laboratory for Materials Science at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
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6
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Hao Q, Long J, Deng X, Tang Y, Abulimiti B, Zhang B. Superexcited State Dynamics of OCS: An Experimental Identification of Three Competing Decay Channels among Autoionization, Internal Conversion, and Neutral Predissociation. J Phys Chem A 2017; 121:3858-3863. [DOI: 10.1021/acs.jpca.7b01895] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Qiaoli Hao
- State
Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China
- University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Jinyou Long
- State
Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China
- University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Xulan Deng
- State
Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China
- University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Ying Tang
- State
Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China
- University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Bumaliya Abulimiti
- College
of Physics and Electronic Engineering, Xinjiang Normal University, Urumqi 830054, PR China
| | - Bing Zhang
- State
Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China
- University of Chinese Academy of Sciences, Beijing 100049, PR China
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7
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Nakashima Y, Harada K, Tanaka K, Tanaka T. High-resolution Fourier transform emission spectroscopy of the A∼2Πi−X∼2Πi band of the OCS +ion. J Chem Phys 2017; 146:144302. [DOI: 10.1063/1.4979300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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8
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Holland D, Shaw D. A study of the valence shell absolute photoabsorption, photoionisation and photodissociation cross sections and the photoionisation quantum efficiency of carbonyl sulphide. Chem Phys 2016. [DOI: 10.1016/j.chemphys.2016.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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9
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Limão-Vieira P, Ferreira da Silva F, Almeida D, Hoshino M, Tanaka H, Mogi D, Tanioka T, Mason NJ, Hoffmann SV, Hubin-Franskin MJ, Delwiche J. Electronic excitation of carbonyl sulphide (COS) by high-resolution vacuum ultraviolet photoabsorption and electron-impact spectroscopy in the energy region from 4 to 11 eV. J Chem Phys 2015; 142:064303. [PMID: 25681902 DOI: 10.1063/1.4907200] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The electronic state spectroscopy of carbonyl sulphide, COS, has been investigated using high resolution vacuum ultraviolet photoabsorption spectroscopy and electron energy loss spectroscopy in the energy range of 4.0-10.8 eV. The spectrum reveals several new features not previously reported in the literature. Vibronic structure has been observed, notably in the low energy absorption dipole forbidden band assigned to the (4π←3π) ((1)Δ←(1)Σ(+)) transition, with a new weak transition assigned to ((1)Σ(-)←(1)Σ(+)) reported here for the first time. The absolute optical oscillator strengths are determined for ground state to (1)Σ(+) and (1)Π transitions. Based on our recent measurements of differential cross sections for the optically allowed ((1)Σ(+) and (1)Π) transitions of COS by electron impact, the optical oscillator strength f0 value and integral cross sections (ICSs) are derived by applying a generalized oscillator strength analysis. Subsequently, ICSs predicted by the scaling are confirmed down to 60 eV in the intermediate energy region. The measured absolute photoabsorption cross sections have been used to calculate the photolysis lifetime of carbonyl sulphide in the upper stratosphere (20-50 km).
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Affiliation(s)
- P Limão-Vieira
- Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - F 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
| | - D Almeida
- Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - M Hoshino
- Department of Physics, Sophia University, Tokyo 102-8554, Japan
| | - H Tanaka
- Department of Physics, Sophia University, Tokyo 102-8554, Japan
| | - D Mogi
- Development and Marketing Department, New Products Development Division, Kanto Denka, Kogyo Co., Ltd., Chiyoda-ku, Tokyo 101-0063, Japan
| | - T Tanioka
- Shibukawa Development Research Laboratory, New Products Development Division, Kanto Denka Kogyo Co., Ltd., Shibukawa City, Gunma 377-8513, Japan
| | - N J Mason
- Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, United Kingdom
| | - S V Hoffmann
- ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Århus C, Denmark
| | - M-J Hubin-Franskin
- Départment de Chimie, Université de Liège, Institut de Chimie-Bât. B6C, allée de la Chimie 3, B-4000 Liège 1, Belgium
| | - J Delwiche
- Départment de Chimie, Université de Liège, Institut de Chimie-Bât. B6C, allée de la Chimie 3, B-4000 Liège 1, Belgium
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10
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Szalay PG, Müller T, Gidofalvi G, Lischka H, Shepard R. Multiconfiguration Self-Consistent Field and Multireference Configuration Interaction Methods and Applications. Chem Rev 2011; 112:108-81. [DOI: 10.1021/cr200137a] [Citation(s) in RCA: 470] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Péter G. Szalay
- Laboratory for Theoretical Chemistry, Institute of Chemistry, Eötvös Loránd University, P. O. Box 32, H-1518 Budapest, Hungary
| | - Thomas Müller
- Jülich Supercomputer Centre, Institute of Advanced Simulation, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Gergely Gidofalvi
- Department of Chemistry and Biochemistry, Gonzaga University, 502 East Boone Avenue, Spokane, Washington 99258-0102, United States
| | - Hans Lischka
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, United States
- Institute for Theoretical Chemistry, University of Vienna, Waehringerstrasse 17, A-1090 Vienna, Austria
| | - Ron Shepard
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
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11
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Brouard M, Green AV, Quadrini F, Vallance C. Photodissociation dynamics of OCS at 248nm: The S(D21) atomic angular momentum polarization. J Chem Phys 2007; 127:084304. [PMID: 17764245 DOI: 10.1063/1.2757618] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The dissociation of OCS has been investigated subsequent to excitation at 248 nm. Speed distributions, speed dependent translational anisotropy parameters, angular momentum alignment, and orientation are reported for the channel leading to S((1)D(2)). In agreement with previous experiments, two product speed regimes have been identified, correlating with differing degrees of rotational excitation in the CO coproducts. The velocity dependence of the translational anisotropy is also shown to be in agreement with previous work. However, contrary to previous interpretations, the speed dependence is shown to primarily reflect the effects of nonaxial recoil and to be consistent with predominant excitation to the 2 (1)A(') electronic state. It is proposed that the associated electronic transition moment is polarized in the molecular plane, at an angle greater than approximately 60 degrees to the initial linear OCS axis. The atomic angular momentum polarization data are interpreted in terms of a simple long-range interaction model to help identify likely surfaces populated during dissociation. Although the model neglects coherence between surfaces, the polarization data are shown to be consistent with the proposed dissociation mechanisms for the two product speed regimes. Large values for the low and high rank in-plane orientation parameters are reported. These are believed to be the first example of a polyatomic system where these effects are found to be of the same order of magnitude as the angular momentum alignment.
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Affiliation(s)
- M Brouard
- The Physical and Theoretical Chemistry Laboratory, The Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom.
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12
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Cossart-Magos C, Jungen M, Stalder J, Launay F. High-resolution absorption spectrum of jet-cooled CH3Cl between 70 000 and 85000cm−1: New assignments. J Chem Phys 2005; 123:104302. [PMID: 16178592 DOI: 10.1063/1.1950671] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The absorption spectrum of jet-cooled CH(3)Cl was photographed from 165 to 117 nm (or 60,000 - 85,000 cm(-1), 7.5-10.5 eV) at a resolution limit of 0.0008 nm (0.3-0.6 cm(-1) or 0.04-0.08 meV). Even in the best structured region of the spectrum, from 70,000 to 85,000 cm(-1) (8.7-10.5 eV), observed bandwidths (full width at half maximum) are large, from 50 to 150 cm(-1). No rotational feature could be resolved. The spectrum is dominated by two strong bands near 9 eV, 140 nm, the D and E bands of Mulliken [J. Chem. Phys. 8, 382 (1940)] or the spectral region D of Price [J. Chem. Phys.4, 539 (1936)]. Their relative intensity is incompatible with previous assignments, namely, to a triplet and a singlet state belonging to the same configuration. On the basis of the present ab initio calculations, those bands are now assigned to two singlet states, the (1)A(1) and (1)E excited states resulting from the 2e(3)4pe Rydberg configuration. The present calculations also reveal that the two (1)E states issued from 2e(3)4sa(1) and 2e(3)4pa(1) are quasidegenerate and strongly mixed. They should be assigned to the two broad bands near 8 eV, 160 nm, the B and C bands of Mulliken and Price. Three vibrational modes are observed to be active: the CCl bond stretch nu(3)(a(1)), and the CH(3) umbrella and rocking vibrations, respectively, nu(2)(a(1)) and nu(6)(e). The fundamental frequencies deduced are well within the ranges defined by the corresponding values in the neutral and ion ground states. The possibility of a dynamical Jahn-Teller effect induced by the nu(6)(e) vibrational mode in the (1)E Rydberg states is discussed.
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Affiliation(s)
- Claudina Cossart-Magos
- Laboratoire de Photophysique Moléculaire du Centre National de la Recherche Scientifique (CNRS), Institut de Physico-Chimie Moléculaire, Université de Paris-Sud, Orsay , France.
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13
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Kim MH, Li W, Lee SK, Suits AG. Probing of the hot-band excitations in the photodissociation of OCS at 288 nm by DC slice imaging. CAN J CHEM 2004. [DOI: 10.1139/v04-072] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The photodissociation dynamics of OCS at 288 nm has been investigated using the DC (direct current) slice imaging technique, which is a recently developed high-resolution "slicing" approach that directly measures the central slice of the photofragment distribution in imaging experiments. By analyzing a DC sliced image of S(1D2) photofragments we observe dissociation originating from OCS molecules excited up to v2 = 4 in the molecular beam. The measured translational energy distribution was used to determine the branching ratio for the contribution from each initial bending state (0 v2 0) of OCS and relative photodissociation cross section ratios compared to v2 = 1. Large negative anisotropy parameters determined as a function of the S(1D2) fragment recoil speed indicate that the photodissociation of OCS at 288 nm occurs exclusively from the 11A′′(1Σ) bending excited potential surface that can be accessed through a perpendicular transition.Key words: DC slicing imaging, OCS, photodissociation, hot-band excitation.
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