1
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Razmus WO, Acheson K, Bucksbaum P, Centurion M, Champenois E, Gabalski I, Hoffman MC, Howard A, Lin MF, Liu Y, Nunes P, Saha S, Shen X, Ware M, Warne EM, Weinacht T, Wilkin K, Yang J, Wolf TJA, Kirrander A, Minns RS, Forbes R. Multichannel photodissociation dynamics in CS 2 studied by ultrafast electron diffraction. Phys Chem Chem Phys 2022; 24:15416-15427. [PMID: 35707953 DOI: 10.1039/d2cp01268e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The structural dynamics of photoexcited gas-phase carbon disulfide (CS2) molecules are investigated using ultrafast electron diffraction. The dynamics were triggered by excitation of the optically bright 1B2(1Σu+) state by an ultraviolet femtosecond laser pulse centred at 200 nm. In accordance with previous studies, rapid vibrational motion facilitates a combination of internal conversion and intersystem crossing to lower-lying electronic states. Photodissociation via these electronic manifolds results in the production of CS fragments in the electronic ground state and dissociated singlet and triplet sulphur atoms. The structural dynamics are extracted from the experiment using a trajectory-fitting filtering approach, revealing the main characteristics of the singlet and triplet dissociation pathways. Finally, the effect of the time-resolution on the experimental signal is considered and an outlook to future experiments provided.
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Affiliation(s)
- Weronika O Razmus
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
| | - Kyle Acheson
- EaStCHEM, School of Chemistry and Centre for Science at Extreme Conditions, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, UK.
| | - Philip Bucksbaum
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Martin Centurion
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
| | - Elio Champenois
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Ian Gabalski
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Matthias C Hoffman
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
| | - Andrew Howard
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Ming-Fu Lin
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
| | - Yusong Liu
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, USA
| | - Pedro Nunes
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
| | - Sajib Saha
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
| | - Xiaozhe Shen
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Matthew Ware
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Emily M Warne
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
| | - Thomas Weinacht
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, USA
| | - Kyle Wilkin
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
| | - Jie Yang
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Thomas J A Wolf
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Adam Kirrander
- EaStCHEM, School of Chemistry and Centre for Science at Extreme Conditions, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, UK.
| | - Russell S Minns
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
| | - Ruaridh Forbes
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
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2
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Karashima S, Suzuki YI, Suzuki T. Ultrafast Extreme Ultraviolet Photoelectron Spectroscopy of Nonadiabatic Photodissociation of CS 2 from 1B 2 ( 1Σ u+) State: Product Formation via an Intermediate Electronic State. J Phys Chem Lett 2021; 12:3755-3761. [PMID: 33844534 DOI: 10.1021/acs.jpclett.1c00864] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We studied nonadiabatic dissociation of CS2 from the 1B2 (1Σu+) state using ultrafast extreme ultraviolet photoelectron spectroscopy. A deep UV (200 nm) laser using the filamentation four-wave mixing method and an extreme UV (21.7 eV) laser using the high-order harmonic generation method were employed to achieve the pump-probe laser cross-correlation time of 48 fs. Spectra measured with a high signal-to-noise ratio revealed clear dynamical features of vibrational wave packet motion in the 1B2 state; its electronic decay to lower electronic state(s) within 630 fs; and dissociation into S(1D2), S(3PJ), and CS fragments within 300 fs. The results suggest that both singlet and triplet dissociation occur via intermediate electronic state(s) produced by electronic relaxation from the 1B2 (1Σu+) state.
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Affiliation(s)
- Shutaro Karashima
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo, Kyoto 606-8502, Japan
| | - Yoshi-Ichi Suzuki
- School of Medical Technology, Health Sciences University of Hokkaido, 1757 Kanazawa, Tobetsucho, Ishikari, Hokkaido 061-0293, Japan
| | - Toshinori Suzuki
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo, Kyoto 606-8502, Japan
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3
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Warne EM, Smith AD, Horke DA, Springate E, Jones AJH, Cacho C, Chapman RT, Minns RS. Time resolved detection of the S(1D) product of the UV induced dissociation of CS2. J Chem Phys 2021; 154:034302. [DOI: 10.1063/5.0035045] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Emily M. Warne
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom
| | - Adam D. Smith
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom
| | - Daniel A. Horke
- Institute for Molecules and Materials, Radboud University, Heijendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Emma Springate
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Alfred J. H. Jones
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Cephise Cacho
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Richard T. Chapman
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Russell S. Minns
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom
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4
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Li Z, Zhao M, Xie T, Luo Z, Chang Y, Cheng G, Yang J, Chen Z, Zhang W, Wu G, Wang X, Yuan K, Yang X. Direct Observation of the C + S 2 Channel in CS 2 Photodissociation. J Phys Chem Lett 2021; 12:844-849. [PMID: 33427476 DOI: 10.1021/acs.jpclett.0c03386] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Carbon disulfide (CS2) is a typical triatomic molecule. Its photodissociation process has generally been assumed to proceed to CS and S primary products via single bond fission. However, recent theoretical calculations suggested that an exit channel to produce C + S2 should also be energetically accessible. Here, we report the direct experimental evidence for the C + S2 channel in CS2 photodissociation by using the velocity map ion imaging technique with two-photon UV and one-photon vacuum UV (VUV) excitations. The detection of the C (3P) products illustrates that the ground state and the electronically excited states of S2 coproducts are formed within highly excited vibrational states. The very weak anisotropic distributions indicate relatively slow dissociation processes. The possible dissociation mechanism involves molecular isomerization of CS2 to linear-CSS from the excited 1B2 (21Σ+) state via vibronic coupling with the 1Π state followed by an avoided crossing with the ground state surface. Our results imply that the S2 molecules observed in comets might be primarily formed in CS2 photodissociation.
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Affiliation(s)
- Zhenxing Li
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Min Zhao
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Ting Xie
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Zijie Luo
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Yao Chang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Gongkui Cheng
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Jiayue Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Zhichao Chen
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Weiqing Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Guorong Wu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Xingan Wang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Kaijun Yuan
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Department of Chemistry, College of Science, Southern University of Science and Technology, Shenzhen 518055, China
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5
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Li Z, Zhao M, Xie T, Chang Y, Luo Z, Chen Z, Wang X, Yuan K, Yang X. Velocity map imaging studies of the photodissociation of CS2 by two-photon excitation at around 303–315 nm. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1813911] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Zhenxing Li
- Department of Chemical Physics, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, People’s Republic of China
| | - Min Zhao
- Department of Chemical Physics, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, People’s Republic of China
| | - Ting Xie
- Department of Chemical Physics, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, People’s Republic of China
| | - Yao Chang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, People’s Republic of China
| | - Zijie Luo
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, People’s Republic of China
| | - Zhichao Chen
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, People’s Republic of China
| | - Xingan Wang
- Department of Chemical Physics, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, People’s Republic of China
| | - Kaijun Yuan
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, People’s Republic of China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, People’s Republic of China
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, People’s Republic of China
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6
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Smith AD, Warne EM, Bellshaw D, Horke DA, Tudorovskya M, Springate E, Jones AJH, Cacho C, Chapman RT, Kirrander A, Minns RS. Mapping the Complete Reaction Path of a Complex Photochemical Reaction. PHYSICAL REVIEW LETTERS 2018; 120:183003. [PMID: 29775354 DOI: 10.1103/physrevlett.120.183003] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Indexed: 06/08/2023]
Abstract
We probe the dynamics of dissociating CS_{2} molecules across the entire reaction pathway upon excitation. Photoelectron spectroscopy measurements using laboratory-generated femtosecond extreme ultraviolet pulses monitor the competing dissociation, internal conversion, and intersystem crossing dynamics. Dissociation occurs either in the initially excited singlet manifold or, via intersystem crossing, in the triplet manifold. Both product channels are monitored and show that, despite being more rapid, the singlet dissociation is the minor product and that triplet state products dominate the final yield. We explain this by a consideration of accurate potential energy curves for both the singlet and triplet states. We propose that rapid internal conversion stabilizes the singlet population dynamically, allowing for singlet-triplet relaxation via intersystem crossing and the efficient formation of spin-forbidden dissociation products on longer timescales. The study demonstrates the importance of measuring the full reaction pathway for defining accurate reaction mechanisms.
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Affiliation(s)
- Adam D Smith
- Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom
| | - Emily M Warne
- Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom
| | - Darren Bellshaw
- EaStCHEM, School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, United Kingdom
| | - Daniel A Horke
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Maria Tudorovskya
- EaStCHEM, School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, United Kingdom
| | - Emma Springate
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Alfred J H Jones
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Cephise Cacho
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Richard T Chapman
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Adam Kirrander
- EaStCHEM, School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, United Kingdom
| | - Russell S Minns
- Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom
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7
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Horio T, Spesyvtsev R, Furumido Y, Suzuki T. Real-time detection of S(1D2) photofragments produced from the 1B2(1Σu+) state of CS2 by vacuum ultraviolet photoelectron imaging using 133 nm probe pulses. J Chem Phys 2017; 147:013932. [DOI: 10.1063/1.4982219] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [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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Spesyvtsev R, Horio T, Suzuki YI, Suzuki T. Observation of the wavepacket dynamics on the 1B2(1Σu+) state of CS2 by sub-20 fs photoelectron imaging using 159 nm probe pulses. J Chem Phys 2015; 142:074308. [DOI: 10.1063/1.4907749] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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9
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Brouard M, Campbell EK, Cireasa R, Johnsen AJ, Yuen WH. The ultraviolet photodissociation of CS2: The S(1D2) channel. J Chem Phys 2012; 136:044310. [DOI: 10.1063/1.3678007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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10
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Brouard M, Campbell EK, Johnsen AJ, Vallance C, Yuen WH, Nomerotski A. Velocity map imaging in time of flight mass spectrometry. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:123115. [PMID: 19123553 DOI: 10.1063/1.3036978] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A new variation on time of flight mass spectrometry is presented, which uses a fast framing charge coupled device camera to velocity map image multiple product masses in a single acquisition. The technique is demonstrated on two photofragmentation processes, those of CS(2) and CH(3)S(2)CH(3) (dimethyldisulfide) at a photolysis wavelength of 193 nm. In both cases, several mass fragments are imaged simultaneously, and speed distributions and anisotropy parameters are extracted that are comparable to those obtained by imaging each fragment separately in conventional velocity map imaging studies.
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Affiliation(s)
- M Brouard
- The Department of Chemistry, The Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom.
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11
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12
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Chen J, Guo Y, Zhou X, Shi Y, Liu S, Ma X. K-Dependent Predissociation Dynamics of CS2 in the 210−216 nm Region. J Phys Chem A 2007; 111:5382-7. [PMID: 17547375 DOI: 10.1021/jp0661894] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The dependence of CS2 predissociation upon rotational quantum number K at vibrational levels below the barrier to linearity of the 1B2(1Sigmau+) state has been investigated in detail with laser spectroscopy, by using a heated supersonic source to increase the intensities of hot band transitions. Predissociation lifetimes were determined from rotational contour simulations of 13 vibronic bands in the CS photofragment excitation (PHOFEX) spectrum, each terminating at the same upper vibrational level but via transitions with different K number (K = 0, 1, 2, respectively). The rovibrational populations of CS fragment at these excitation bands were derived from the laser-induced fluorescence (LIF) spectrum, and were used further to obtain the dissociation branching ratios S(1D)/S(3P) as well as the excess energy partitionings after dissociation. The lifetimes and the branching ratios were found to be sensitively dependent on quantum number K; the lifetime decreases with the increase of K, and the branching ratio increases with K. Analysis shows that quantum number K influences the S(1D) channel more effectively than the S(3P) channel. About 28 and 15% of the total available energy is taken up by the CS vibrational and rotational degrees of freedom, respectively. Systematic analysis indicates that the two electronic states interacting with 1B2(1Sigmau+) state should be bent, and the state correlating with S(1D) channel should be more bent.
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Affiliation(s)
- Jun Chen
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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13
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Townsend D, Satzger H, Ejdrup T, Lee AMD, Stapelfeldt H, Stolow A. B21(Σu+1) excited state decay dynamics in CS2. J Chem Phys 2006; 125:234302. [PMID: 17190553 DOI: 10.1063/1.2403137] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The authors report time resolved photoelectron spectra of the (1)B(2)((1)Sigma(u) (+)) state of CS(2) at pump wavelengths in the region of 200 nm. In contrast to previous studies, the authors find that the predissociation dynamics is not well described by a single exponential decay. Biexponential modeling of the authors' data reveals a rapid decay pathway (tau<50 fs), in addition to a longer lived channel (tau approximately 350-650 fs) that displays a marked change in apparent lifetime when the polarization of the pump laser is rotated with respect to that of the probe. Since the initially populated (1)B(2)((1)Sigma(u) (+)) state may decay to form either S((1)D) or S((3)P) products (the latter produced via a spin-orbit induced crossing from a singlet to a triplet electronic surface), this lifetime observation may be rationalized in terms of changes in the relative ionization cross section of these singlet and triplet states of CS(2) as a function of laser polarization geometry. The experimentally observed lifetime of the longer lived channel is therefore a superposition of these two pathways, both of which decay on very similar time scales.
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Affiliation(s)
- Dave Townsend
- Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, Ontario KIA 0R6, Canada
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14
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Huang J, Xu D, Stuchebrukhov A, Jackson WM. Single-photon spectroscopy of singlet sulfur atoms and the autoionization lifetime measurements of the superexcited singlet states. J Chem Phys 2005; 122:144321. [PMID: 15847536 DOI: 10.1063/1.1875032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Single-photon excitation spectra from the lowest singlet (1)D(2) level of sulfur atoms were recorded with a tunable vacuum ultraviolet (VUV) radiation source generated by frequency tripling in noble gases. The photolysis of CS(2) at 193 nm was used to produce the singlet S((1)D(2)) sulfur atoms that were then excited to neutral superexcited states with the tunable VUV radiation. These superexcited states undergo autoionization into the first ionization continuum state of S(+)((4)S(3/2) (o))+e(-), which is not directly accessible from the S((1)D(2)) state via an allowed transition. The excitation spectra were recorded by monitoring the S(+) signal in a velocity imaging apparatus while scanning the VUV excitation wavelength. Three new lines were observed in the spectra which have not been previously reported. The full widths at half maximum (FWHM) of each of the observed transitions were determined by fitting the profiles of each absorption resonances with the Fano formula. Autoionization lifetimes tau of these singlet superexcited states were obtained from FWHM using the Uncertainty Principle. Abnormal autoionization lifetimes were found for the 3s(2)3p(3)((2)D(o))nd((1)D(2)) and the 3s(2)3p(3)((2)D(o))ns((1)D(2)) Rydberg series, in which tau(5d) and tau(7s) are shorter than tau(4d) and tau(6s), respectively. This is contrary to the well-known scaling law of tau(n*) proportional, variantn(*3), which should be followed within a series unless there exist perturbations from other series or new channels open up to which some members of the series can decay. Possible perturbations from the nearby triplet series are suspected for causing the broadening of the 5d and 7s levels.
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Affiliation(s)
- Jianhua Huang
- Department of Chemistry, University of California, Davis, California 95616, USA
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15
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Khachatrian A, Dagdigian PJ. Determination of the internal state distribution of the SD product from the S(1D)+D2 reaction. J Chem Phys 2005; 122:024303. [PMID: 15638582 DOI: 10.1063/1.1827598] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The S(1D)+D2-->SD+D reaction has been studied through a photolysis-probe experiment in a cell. S(1D) reagent was prepared by 193 nm photolysis of CS2, and the SD(X 2Pi) product was detected by laser fluorescence excitation. The nascent rotational/fine-structure state distribution of the SD(X 2Pi) product was determined. This reaction, previously studied theoretically and in a crossed molecular beam experiment, is known to proceed through formation and decay of a long-lived collision complex involving the deep well in the H2S ground electronic state. The determined SD rotational state distribution in the v=0 vibrational level was found to be approximately statistical, with a small preference for formation of the F1 (Omega=3/2) fine-structure manifold over F2 (Omega=1/2). The branching into the Lambda doublet levels was also investigated, and essentially equal populations of levels of A' and A" symmetry were found. The present results are compared with previous investigations of this reaction and the analogous O(1D)+D2 reaction.
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Affiliation(s)
- Ani Khachatrian
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218-2685, USA
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16
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Huang J, Xu D, Stuchebrukhov A, Jackson WM. Measurement of the autoionization lifetime of the superexcited atomic sulfur S(3s23p3(2Do)4d) state using tunable vacuum ultraviolet (VUV) radiation. CAN J CHEM 2004. [DOI: 10.1139/v04-039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A new method is described that combines a tunable coherent vacuum ultraviolet (VUV) radiation source and an ion velocity imaging apparatus to study the autoionization of superexcited sulfur atoms. The photolysis of CS2 at 193 nm is used to produce metastable sulfur atoms in the 1D2 state. The S(1D2) atom is then directly excited to the neutral superexcited state 3s23p3(2Do)4d (1Do2) at 11.317 eV with a tunable VUV photon at ~121.896 nm. This excited state then undergoes autoionization into the first ionization continuum state of S+(4So3/2) + e, which is not directly accessible from the S(1D2) state through optical transition. By monitoring the S+ signal in the time-of-flight mass spectrometer while scanning the excitation wavelength, the line profile of the 3s23p34d 1Do2 ← 3s23p4 1D2 transition is recorded and found to have a full width at half maximum (FWHM) of 0.9 cm1. This has been used to determine an autoionization lifetime of the neutral superexcited 3s23p34d 1Do2 state of 5.9 ps. The accurate measurement of the autoionization lifetime provides a benchmark for testing fundamental theoretical models of processes occurring in excited states of atoms. Key words: autoionization, atomic sulfur, vacuum ultraviolet (VUV), full width at half maximum (FWHM).
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17
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Xu D, Huang J, Jackson WM. Reinvestigation of CS2 dissociation at 193 nm by means of product state-selective vacuum ultraviolet laser ionization and velocity imaging. J Chem Phys 2004; 120:3051-4. [PMID: 15268456 DOI: 10.1063/1.1646671] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A branching ratio of 1.6 +/- 0.3 for S(3P)/S(1D) is obtained for the dissociation of CS2 with very low fluence 193 nm laser (less than 2 mJ/cm2), in which the S(3P) and S(1D) have been state-selectively ionized using VUV lasers at different wavelengths. The anisotropy parameters betamax(3P) = 0.8 and betamax(1D) = 1.9 indicate that these channels are preferentially populated at different geometries and the lifetime is very short.
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Affiliation(s)
- Dadong Xu
- Department of Chemistry, University of California-Davis, Davis, California 95616, USA
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Detection of Parent Molecules in Comets using UV and Visible Spectroscopy. ACTA ACUST UNITED AC 2004. [DOI: 10.1007/978-1-4020-2573-0_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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Qi F, Suits AG. Photodissociation of Propylene Sulfide at 193 nm: A Photofragment Translational Spectroscopy Study with VUV Synchrotron Radiation. J Phys Chem A 2002. [DOI: 10.1021/jp026084a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Fei Qi
- Chemical Sciences Division, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Arthur G. Suits
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, and Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973
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Qi F, Sheng L, Ahmed M, Peterka DS, Baer T. Exclusive production of excited-state sulfur (1D) atoms from 193 nm photolysis of thietane. Chem Phys Lett 2002. [DOI: 10.1016/s0009-2614(02)00492-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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21
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Kitsopoulos TN, Gebhardt CR, Rakitzis TP. Photodissociation study of CS2 at 193 nm using slice imaging. J Chem Phys 2001. [DOI: 10.1063/1.1415436] [Citation(s) in RCA: 41] [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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Qi F, Sorkhabi O, Suits AG, Chien SH, Li WK. Photodissociation of ethylene sulfide at 193 nm: a photofragment translational spectroscopy study with VUV synchrotron radiation and ab initio calculations. J Am Chem Soc 2001; 123:148-61. [PMID: 11273612 DOI: 10.1021/ja003314v] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Photodissociation of ethylene sulfide at 193 nm has been studied using photofragment translational spectroscopy and ab initio theoretical calculations. Tunable synchrotron radiation was used as a universal but selective probe of the reaction products to reveal new aspects of the photodissociation dynamics. The channel giving S + C2H4 was found to be dominated by production of ground-state sulfur atoms (S(3P):S(1D) = 1.44:1), mostly through a spin-forbidden process. The results also suggest the presence of a channel giving S(3P) in conjunction with triplet ethylene C2H4 (3B(1u)) and allow insight into the energy of the latter species near its equilibrium geometry, in which the two methylene groups occupy perpendicular planes. In addition, a channel leading to the production of H2S with C2H2 also has been observed. Our experimental results are supported and elaborated by theoretical calculations.
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Affiliation(s)
- F Qi
- Chemical Sciences Division, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
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Qi F, Sorkhabi O, Suits AG. Evidence of triplet ethylene produced from photodissociation of ethylene sulfide. J Chem Phys 2000. [DOI: 10.1063/1.481713] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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