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Wang P, Lin Q, Xiao C, Yang X, Liu K, Pan H. Unraveling the Photodissociation Branching and Pathways of Methane at 118 nm by Imaging the CH 3, CH 2, and CH Fragments. J Phys Chem A 2024; 128:5273-5284. [PMID: 38946501 DOI: 10.1021/acs.jpca.4c01914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Under irradiation of a vacuum ultraviolet (VUV) photon, methane dissociates and yields multiple fragments. This photochemical behavior is not only of fundamental importance but also with wide-ranging implications in several branches of science. Despite that and numerous previous investigations, the product channel branching is still under debate, and the underlying dissociation mechanisms remain elusive. In this study, the photofragment imaging technique was exploited for the first time to map out the momentum and anisotropy parameter distributions of the CH3, CH2, and CH fragments at the 118 nm photolysis wavelength (10.48 eV photon energy). In conjunction with previously reported results of the H atom fragment at 121.6 nm (10.2 eV), a complete set of product channel branching in both two-body and three-body fragmentations is accurately determined. We concluded that extensive nonadiabatic transitions partake in the processes with two-body fragmentations accounting for more than 90% of overall photodissociation, for which the channel branching values for CH2 + H2 and CH3 + H are about 0.66 and 0.25, respectively. Careful kinematic analysis enables us to untangle the intertwined triple fragmentations into the CH2(X̃ 3B1 and ã 1A1) + H + H and CH(X2Π) + H + H2 channels and to evidence their underlying sequential (or stepwise) mechanisms. With the aid of electronic correlation and prior theoretical calculations of the potential energy surfaces, the most probable or dominant dissociation pathways are elucidated. Comparisons with fragmentary reports in the literature on various photochemical aspects are also documented, and discrepancies are clarified. This comprehensive study benchmarks the VUV photochemistry of methane and advances our understanding of this important process.
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Affiliation(s)
- Pengcheng Wang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, CAS, Dalian 116023, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Qiaosong Lin
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, CAS, Dalian 116023, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Chunlei Xiao
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, CAS, Dalian 116023, P. R. China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, CAS, Dalian 116023, P. R. China
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Kopin Liu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, CAS, Dalian 116023, P. R. China
- Aerosol Science Research Center, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Taipei 10617, Taiwan
| | - Huilin Pan
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, CAS, Dalian 116023, P. R. China
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, P. R. China
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Sutradhar S, Samanta BR, Fernando R, Reisler H. Spectroscopy and Two-Photon Dissociation of Jet-Cooled Pyruvic Acid. J Phys Chem A 2019; 123:5906-5917. [DOI: 10.1021/acs.jpca.9b04166] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Subhasish Sutradhar
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Bibek R. Samanta
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Ravin Fernando
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Hanna Reisler
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
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Hobday N, Quinn MS, Nauta K, Andrews DU, Jordan MJT, Kable SH. Experimental and Theoretical Investigation of Triple Fragmentation in the Photodissociation Dynamics of H2CO. J Phys Chem A 2013; 117:12091-103. [DOI: 10.1021/jp404895y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nicholas Hobday
- School of Chemistry, University of Sydney, Sydney NSW 2006, Australia
| | - Mitch S. Quinn
- School of Chemistry, University of Sydney, Sydney NSW 2006, Australia
| | - Klaas Nauta
- School of Chemistry, University of Sydney, Sydney NSW 2006, Australia
| | - Duncan U. Andrews
- School of Chemistry, University of Sydney, Sydney NSW 2006, Australia
| | | | - Scott H. Kable
- School of Chemistry, University of Sydney, Sydney NSW 2006, Australia
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Fang Q, Zhang F, Shen L, Fang WH, Luo Y. Photodissociation of phosgene: Theoretical evidence for the ultrafast and synchronous concerted three-body process. J Chem Phys 2009; 131:164306. [DOI: 10.1063/1.3253048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Chen WK, Cheng PY. Ultrafast photodissociation dynamics of acetone at 195 nm: II. Unraveling complex three-body dissociation dynamics by femtosecond time-resolved photofragment translational spectroscopy. J Phys Chem A 2007; 109:6818-29. [PMID: 16834037 DOI: 10.1021/jp0509717] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
As a continuation of the preceding paper in this issue (J. Phys. Chem. A 2005, 109, 6805), we studied photodissociation dynamics of the acetone S2 (n, 3s) Rydberg state excited at 195 nm using femtosecond time-resolved photofragment translational spectroscopy. The technique, which is implemented by the combination of fs pump-probe ionization spectroscopy and kinetic energy resolved time-of-flight mass spectrometry (KETOF), measured temporal evolutions of the product kinetic energy distributions (KEDs) with a time resolution limited only by the laser pulse widths. Two methyl product KED components were resolved and assigned to the primary and secondary methyl products on the basis of their temporal behaviors. The results support the mechanism in which the primary dissociation occurs on the acetone S1 surface and provide complementary dynamical information to that discussed in the preceding paper.
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Affiliation(s)
- Wei-Kan Chen
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan, ROC
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Maul C, Chichinin A. Is spin-orbit state branching in the photodissociation of CCl4 isotope specific? J Photochem Photobiol A Chem 2007. [DOI: 10.1016/j.jphotochem.2006.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Spectroscopy and kinetics of the gas phase addition complex of atomic chlorine with dimethyl sulfoxide. J Photochem Photobiol A Chem 2007. [DOI: 10.1016/j.jphotochem.2006.08.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Chichinin AI, Einfeld T, Maul C, Gericke KH. Direct observation of the three-dimensional velocity distributions of Cl(2 P 3/2,1/2) atoms in the photodissociation of selected chlorides. DOKLADY PHYSICAL CHEMISTRY 2006. [DOI: 10.1134/s0012501606030043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Chichinin A, Einfeld TS, Gericke KH, Grunenberg J, Maul C, Schäfer LV. Photodissociation dynamics of SOCl2. Phys Chem Chem Phys 2005; 7:301-9. [DOI: 10.1039/b412797h] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Tanaka N, Tamezane T, Nishikiori H, Fujii T, Sisk WN. Theoretical studies on carbonyl halide–water complexes. Chem Phys 2004. [DOI: 10.1016/j.chemphys.2004.07.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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YAMAMOTO S, AMEMIYA T, MURABAYASHI M, ITOH K. Dual-Light-Source Direct Photodegradation of Trichloroethylene in the Gas-phase―Effects on Slightly Degradable By-Products. ELECTROCHEMISTRY 2004. [DOI: 10.5796/electrochemistry.72.495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Shin YAMAMOTO
- Graduate School of Environment and Information Sciences, Yokohama National University
| | - Takashi AMEMIYA
- Graduate School of Environment and Information Sciences, Yokohama National University
| | - Masayuki MURABAYASHI
- Graduate School of Environment and Information Sciences, Yokohama National University
| | - Kiminori ITOH
- Graduate School of Environment and Information Sciences, Yokohama National University
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Roth M, Maul C, Gericke KH. Photodissociation Dynamics of Cl2O: Interpretation of Electronic Transitions. J Phys Chem A 2004. [DOI: 10.1021/jp049334r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Melanie Roth
- Institut für Physikalische und Theoretische Chemie, Technische Universität Braunschweig, Hans-Sommer-Strasse 10, 38106 Braunschweig, Germany
| | - Christof Maul
- Institut für Physikalische und Theoretische Chemie, Technische Universität Braunschweig, Hans-Sommer-Strasse 10, 38106 Braunschweig, Germany
| | - Karl-Heinz Gericke
- Institut für Physikalische und Theoretische Chemie, Technische Universität Braunschweig, Hans-Sommer-Strasse 10, 38106 Braunschweig, Germany
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Abstract
We discuss experiments on the dynamics of photodissociation that employ methods to select the energy, sometimes quantum states, of the reactant and to determine the quantum states and energy, sometimes also the orientation and alignment, of products. A summary of new advances of experimental methods is followed by applications to photodissociation of various types. Representative examples of simple bond fission, molecular elimination, and three-body dissociation with determined electronic states-sometimes the orientation of their angular momentum-of product atoms or distributions of electronic and internal states of product molecules illustrate the detailed information and insight that one can derive from such experiments. Photodissociation of van der Waals complexes, ions, species adsorbed on surfaces, and species in solution is excluded from this review.
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Affiliation(s)
- Yuan-Pern Lee
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan.
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Einfeld T, Chichinin A, Maul C, Gericke KH. Photodissociation dynamics of phosgene: New observations by applying a three-dimensional imaging technique. J Chem Phys 2002. [DOI: 10.1063/1.1427072] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Kwon HT, Shin SK, Kim SK, Kim HL, Park CR. Photodissociation Dynamics of Acetic Acid and Trifluoroacetic Acid at 193 nm. J Phys Chem A 2001. [DOI: 10.1021/jp010787v] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hyuk Tae Kwon
- Department of Chemistry, Kangwon National University, Chuncheon 200-701, Korea
| | - Seung Keun Shin
- Department of Chemistry, Kangwon National University, Chuncheon 200-701, Korea
| | - Sang Kyu Kim
- Department of Chemistry, Kangwon National University, Chuncheon 200-701, Korea
| | - Hong Lae Kim
- Department of Chemistry, Kangwon National University, Chuncheon 200-701, Korea
| | - Chan Ryang Park
- Department of Chemistry, College of Natural Sciences, Kookmin University, Seoul 136-702, Korea
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Affiliation(s)
- Christof Maul
- Institut für Physikalische und Theoretische Chemie, Technische Universität Braunschweig, Hans-Sommer-Strasse 10, D-38106 Braunschweig, Germany
| | - Karl-Heinz Gericke
- Institut für Physikalische und Theoretische Chemie, Technische Universität Braunschweig, Hans-Sommer-Strasse 10, D-38106 Braunschweig, Germany
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