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Vinklárek IS, Suchan J, Rakovský J, Moriová K, Poterya V, Slavíček P, Fárník M. Energy partitioning and spin-orbit effects in the photodissociation of higher chloroalkanes. Phys Chem Chem Phys 2021; 23:14340-14351. [PMID: 34169306 DOI: 10.1039/d1cp01371h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We investigate the photodissociation dynamics of the C-Cl bond in chloroalkanes CH3Cl, n-C3H7Cl, i-C3H7Cl, n-C5H11Cl, combining velocity map imaging (VMI) experiment and direct ab initio dynamical simulations. The Cl fragment kinetic energy distributions (KEDs) from the VMI experiment exhibit a single peak with maximum close to 0.8 eV, irrespective of the alkyl chain length and C-Cl bond position. In contrary to CH3Cl, where less than 10% of the available energy is deposited into the internal excitation of the CH3 fragment, for all higher chloroalkanes around 40% to 60% of the available energy goes into the alkyl fragment excitation. We apply the classical hard spheres and spectator model to explain the energy partitioning, and compare the classical approach with direct ab initio dynamics simulations. The alkyl chain appears to be a soft, energy absorbing unit. We further investigate the role of the spin-orbit effects on the excitation and dynamics. Combining our experimental data with theory allows us to derive the probability of the direct absorption into the triplet electronic state as well as the probabilities for intersystem crossing. The results indicate an increasing direct absorption into the triplet state with increasing alkyl chain length.
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Affiliation(s)
- Ivo S Vinklárek
- J. Heyrovský Institute of Physical Chemistry, v.v.i., The Czech Academy of Sciences, Dolejškova 2155/3, 182 23 Prague 8, Czech Republic.
| | - Jiří Suchan
- University of Chemistry and Technology, 166 28 Prague 6, Czech Republic.
| | - Jozef Rakovský
- J. Heyrovský Institute of Physical Chemistry, v.v.i., The Czech Academy of Sciences, Dolejškova 2155/3, 182 23 Prague 8, Czech Republic.
| | - Kamila Moriová
- J. Heyrovský Institute of Physical Chemistry, v.v.i., The Czech Academy of Sciences, Dolejškova 2155/3, 182 23 Prague 8, Czech Republic.
| | - Viktoriya Poterya
- J. Heyrovský Institute of Physical Chemistry, v.v.i., The Czech Academy of Sciences, Dolejškova 2155/3, 182 23 Prague 8, Czech Republic.
| | - Petr Slavíček
- University of Chemistry and Technology, 166 28 Prague 6, Czech Republic.
| | - Michal Fárník
- J. Heyrovský Institute of Physical Chemistry, v.v.i., The Czech Academy of Sciences, Dolejškova 2155/3, 182 23 Prague 8, Czech Republic.
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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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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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Hu Z, Lee WB, Zhang XP, Wei PY, Lin KC. (1+1) Resonance-Enhanced Multiphoton Ionization and Photodissociation Study of CS2 via the1B2 State. Chemphyschem 2008; 9:422-30. [DOI: 10.1002/cphc.200700620] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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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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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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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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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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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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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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McGivern WS, Sorkhabi O, Rizvi AH, Suits AG, North SW. Photofragment translational spectroscopy with state-selective “universal detection:” The ultraviolet photodissociation of CS2. J Chem Phys 2000. [DOI: 10.1063/1.481101] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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13
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Farmanara P, Stert V, Radloff W. Ultrafast predissociation and coherent phenomena in CS2 excited by femtosecond laser pulses at 194–207 nm. J Chem Phys 1999. [DOI: 10.1063/1.479793] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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14
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Beatty AS, Shiell RC, Chang D, Hepburn JW. Resonance enhanced multiphoton ionization spectroscopy of jet cooled 12C32S2 and 12C34S32S from 45 500 to 48 000 cm−1. J Chem Phys 1999. [DOI: 10.1063/1.478756] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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Arendt MF, Butler LJ. Emission spectroscopy of jet-cooled CS2 upon excitation of the 1Σg+→1B2(1Σu+) transition in the 48 500–51 000 cm−1 region. J Chem Phys 1998. [DOI: 10.1063/1.477430] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Samartzis PC, Kitsopoulos TN. Two-Photon Dissociation Study of CS2 Using Ion Imaging. J Phys Chem A 1997. [DOI: 10.1021/jp9703667] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Peter C. Samartzis
- Department of Chemistry, University of Crete and Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, 711 10 Heraklion-Crete, Greece
| | - Theofanis N. Kitsopoulos
- Department of Chemistry, University of Crete and Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, 711 10 Heraklion-Crete, Greece
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