1
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Liu Q, Tan S, Zou X, Liu P, Yu S. Wavelength-Dependent Dynamics of the O( 1D 2) Channel in the 1Δ u State Photodissociation of CO 2. J Phys Chem A 2024; 128:2989-2996. [PMID: 38572621 DOI: 10.1021/acs.jpca.4c00223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024]
Abstract
The wavelength-dependent dynamics of the O(1D2) channel, formed by photoexcitation of CO2 to the 1Δu state at 143.53-153.03 nm, is investigated by using the time-sliced velocity-mapped ion imaging method. The measured ionic peaks of the O(1D2) images are analyzed to determine the total kinetic energy release (TKER) spectra and image anisotropy parameters. The structures observed in the TKER spectra can be directly assigned to the ro-vibrational state distributions of the counter CO photofragments. Compared to those observed at 157 and 155 nm, the highly rotationally excited CO photofragments still obviously appear in v = 0 and 1, but the fraction of rotational excitations is significantly reduced. Conversely, the CO photofragments exhibit substantially higher vibrational excitations, implying that the nearly linear 21A' state also contributes to dissociation in addition to the bend configuration. The image anisotropy parameters display an extremely slow decreasing trend with an increase of the CO ro-vibrational state besides those for the highest ro-vibrationally excited CO photofragments. Nevertheless, the nonaxial recoil effect, suggested in previous photodissociation studies of CO2 and other triatomic molecular systems, is still appropriate to explain the observations of internal energy dependences of image anisotropy parameters.
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Affiliation(s)
- Qian Liu
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China
| | - Sha Tan
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China
| | - Xiaolan Zou
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China
| | - Peng Liu
- 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
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2
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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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3
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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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4
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Karamatskos ET, Yarlagadda S, Patchkovskii S, Vrakking MJJ, Welsch R, Küpper J, Rouzée A. Time-resolving the UV-initiated photodissociation dynamics of OCS. Faraday Discuss 2021; 228:413-431. [PMID: 33570531 DOI: 10.1039/d0fd00119h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We present a time-resolved study of the photodissociation dynamics of OCS after UV-photoexcitation at λ = 237 nm. OCS molecules (X1Σ+) were primarily excited to the 11A'' and the 21A' Renner-Teller components of the 1Σ- and 1Δ states. Dissociation into CO and S fragments was observed through time-delayed strong-field ionisation and imaging of the kinetic energy of the resulting CO+ and S+ fragments by intense 790 nm laser pulses. Surprisingly, fast oscillations with a period of ∼100 fs were observed in the S+ channel of the UV dissociation. Based on wavepacket-dynamics simulations coupled with a simple electrostatic-interaction model, these oscillations do not correspond to the known highly-excited rotational motion of the leaving CO(X1Σ+, J ≫ 0) fragments, which has a timescale of ∼140 fs. Instead, we suggest to assign the observed oscillations to the excitation of vibrational wavepackets in the 23A'' or 21A'' states of the molecule that predissociate to form S(3PJ) photoproducts.
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Affiliation(s)
- Evangelos T Karamatskos
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany. and Department of Physics, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | | | | | | | - Ralph Welsch
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany. and Center for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Jochen Küpper
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany. and Department of Physics, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany and Center for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Arnaud Rouzée
- Max Born Institute, Max-Born-Straße 2a, 12489 Berlin, Germany.
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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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6
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Bai XL, Zhao DF, Chen Y. Photodissociation dynamics of OCS at 207 nm: S( 1D 2)+CO( X1Σ +) product channel. CHINESE J CHEM PHYS 2020. [DOI: 10.1063/1674-0068/cjcp1908148] [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]
Affiliation(s)
- Xi-lin Bai
- School of Physics and Information Engineering, Shanxi Normal University, Linfen 041004, China
| | - Dong-feng Zhao
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yang Chen
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
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7
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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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8
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Suits AG. Invited Review Article: Photofragment imaging. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:111101. [PMID: 30501356 DOI: 10.1063/1.5045325] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 10/25/2018] [Indexed: 06/09/2023]
Abstract
Photodissociation studies in molecular beams that employ position-sensitive particle detection to map product recoil velocities emerged thirty years ago and continue to evolve with new laser and detector technologies. These powerful methods allow application of tunable laser detection of single product quantum states, simultaneous measurement of velocity and angular momentum polarization, measurement of joint product state distributions for the detected and undetected products, coincident detection of multiple product channels, and application to radicals and ions as well as closed-shell molecules. These studies have permitted deep investigation of photochemical dynamics for a broad range of systems, revealed new reaction mechanisms, and addressed problems of practical importance in atmospheric, combustion, and interstellar chemistry. This review presents an historical overview, a detailed technical account of the range of methods employed, and selected experimental highlights illustrating the capabilities of the method.
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Affiliation(s)
- Arthur G Suits
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, USA
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9
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Bai XL, Liang H, Zhou ZF, Hua ZF, Zhao DF, Chen Y. Photodissociation Dynamics of OCS at 217 nm. CHINESE J CHEM PHYS 2017. [DOI: 10.1063/1674-0068/30/cjcp1705092] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Xi-lin Bai
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical physics, University of Science and Technology of China, Hefei 230026, China
| | - Hao Liang
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical physics, University of Science and Technology of China, Hefei 230026, China
| | - Zheng-fang Zhou
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical physics, University of Science and Technology of China, Hefei 230026, China
| | - Ze-feng Hua
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical physics, University of Science and Technology of China, Hefei 230026, China
| | - Dong-feng Zhao
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical physics, University of Science and Technology of China, Hefei 230026, China
| | - Yang Chen
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical physics, University of Science and Technology of China, Hefei 230026, China
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10
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Bai X, Liang H, Zhou Z, Hua Z, Jiang B, Zhao D, Chen Y. Photodissociation dynamics of OCS at ∼210 nm: The role of c(23A″) state. J Chem Phys 2017; 147:013930. [DOI: 10.1063/1.4982684] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Xilin Bai
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
| | - Hao Liang
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
| | - Zhengfang Zhou
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
| | - Zefeng Hua
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
| | - Bin Jiang
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
| | - Dongfeng Zhao
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
| | - Yang Chen
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
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11
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Tsai PY. On the state selection of linear triatomic molecules by electrostatic hexapole fields. J Chem Phys 2016; 145:104311. [PMID: 27634264 DOI: 10.1063/1.4962359] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Electrostatic hexapole state-selector is a versatile tool in experimental stereodynamics. The requirement of appropriate models to correctly predict the behavior of molecules in the hexapole motivated us to realize a treatment that predicts the Stark effect of linear triatomic molecules with rotational doublet states. Various perturbative approximations are conventionally adopted to obtain analytic Stark energy derivatives of a truncated Hamiltonian matrix, without utilizing numerical diagonalization of the full Hamiltonian matrix. By including both the low and high field effects, which were alternatively ignored in the analytical formulae of such approximate approaches, herein we demonstrate that the performance of hexapole state selector to linear triatomic molecules can be appropriately predicted via Van Vleck transformation. This method can provide analytic Stark energy derivatives that are acceptably in consistent with the ones obtained via numerical diagonalization of the full Hamiltonian matrix. Particularly, this work is suitable for v2 = 1 level of linear triatomic molecules, due to the following reasons: (1) the Stark energy derivative and the molecular orientation as a function of the electric field are expressed in analytical formulae, hence it is suitable for implementation without involving numerical diagonalization of the full Hamiltonian matrix; (2) a better prediction of the focusing curves with respect to conventional analytical treatments is provided, allowing a reliable determination of the selected state compositions and molecular orientation.
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Affiliation(s)
- Po-Yu Tsai
- Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan
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12
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Toulson BW, Murray C. Decomposing the First Absorption Band of OCS Using Photofragment Excitation Spectroscopy. J Phys Chem A 2016; 120:6745-52. [PMID: 27552402 DOI: 10.1021/acs.jpca.6b06060] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Photofragment excitation spectra of carbonyl sulfide (OCS) have been recorded from 212-260 nm by state-selectively probing either electronically excited S((1)D) or ground state S((3)P) photolysis products via 2 + 1 resonance-enhanced multiphoton ionization. Probing the major S((1)D) product results in a broad, unstructured action spectrum that reproduces the overall shape of the first absorption band. In contrast, spectra obtained probing S((3)P) products display prominent resonances superimposed on a broad continuum; the resonances correspond to the diffuse vibrational structure observed in the conventional absorption spectrum. The vibrational structure is assigned to four progressions, each dominated by the C-S stretch, ν1, following direct excitation to quasi-bound singlet and triplet states. The S((3)PJ) products are formed with a near-statistical population distribution over the J = 2, 1, and 0 spin-orbit levels across the wavelength range investigated. Although a minor contributor to the S atom yield near the peak of the absorption cross section, the relative yield of S((3)P) increases significantly at longer wavelengths. The experimental measurements validate recent theoretical work characterizing the electronic states responsible for the first absorption band by Schmidt and co-workers.
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Affiliation(s)
- Benjamin W Toulson
- Department of Chemistry, University of California, Irvine , Irvine, California 92697, United States
| | - Craig Murray
- Department of Chemistry, University of California, Irvine , Irvine, California 92697, United States
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13
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Wei W, Wallace CJ, McBane GC, North SW. Photodissociation dynamics of OCS near 214 nm using ion imaging. J Chem Phys 2016; 145:024310. [PMID: 27421408 DOI: 10.1063/1.4955189] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The OCS photodissociation dynamics of the dominant S((1)D2) channel near 214 nm have been studied using velocity map ion imaging. We report a CO vibrational branching ratio of 0.79:0.21 for v = 0:v = 1, indicating substantially higher vibrational excitation than that observed at slightly longer wavelengths. The CO rotational distribution is bimodal for both v = 0 and v = 1, although the bimodality is less pronounced than at longer wavelengths. Vector correlations, including rotational alignment, indicate that absorption to both the 2(1)A' (A) and 1(1)A″ (B) states is important in the lower-j part of the rotational distribution, while only 2(1)A' state absorption contributes to the upper part; this conclusion is consistent with work at longer wavelengths. Classical trajectory calculations including surface hopping reproduce the measured CO rotational distributions and their dependence on wavelength well, though they underestimate the v = 1 population. The calculations indicate that the higher-j peak in the rotational distribution arises from molecules that begin on the 2(1)A' state but make nonadiabatic transitions to the 1(1)A' (X) state during the dissociation, while the lower-j peak arises from direct photodissociation on either the 2(1)A' or the 1(1)A″ states, as found in previous work.
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Affiliation(s)
- Wei Wei
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, USA
| | - Colin J Wallace
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, USA
| | - George C McBane
- Department of Chemistry, Grand Valley State University, Allendale, Michigan 49401, USA
| | - Simon W North
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, USA
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14
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Toulson BW, Alaniz JP, Grant Hill J, Murray C. Near-UV photodissociation dynamics of CH2I2. Phys Chem Chem Phys 2016; 18:11091-103. [DOI: 10.1039/c6cp01063f] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The near-UV photodissociation dynamics of CH2I2has been investigated using a combination of velocity-map (slice) ion imaging andab initiocalculations characterizing the excited states.
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Affiliation(s)
| | | | - J. Grant Hill
- Department of Chemistry
- University of Sheffield
- Sheffield S3 7HF
- UK
| | - Craig Murray
- Department of Chemistry
- University of California, Irvine
- Irvine
- USA
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Schmidt JA, Olsen JMH. Photodissociation of OCS: Deviations between theory and experiment, and the importance of higher order correlation effects. J Chem Phys 2014; 141:184310. [DOI: 10.1063/1.4901426] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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McBane GC, Schmidt JA, Johnson MS, Schinke R. Ultraviolet photodissociation of OCS: Product energy and angular distributions. J Chem Phys 2013; 138:094314. [DOI: 10.1063/1.4793275] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Schmidt JA, Johnson MS, McBane GC, Schinke R. The ultraviolet spectrum of OCS from first principles: Electronic transitions, vibrational structure and temperature dependence. J Chem Phys 2012; 137:054313. [DOI: 10.1063/1.4739756] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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18
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Photofragment angular momentum polarization in the photolysis of symmetric top molecules: Production, detection, and rotational depolarization. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2011.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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