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Kim J, Kim SK. Multiphoton-excited dynamics of the trans or cis structural isomer of 1,2-dibromoethylene. J Chem Phys 2021; 155:164304. [PMID: 34717354 DOI: 10.1063/5.0067643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Photofragmentation dynamics of cis and trans isomers of 1,2-dibromoethylene (1,2-DBE) have been investigated by multiphoton excitation using a picosecond (ps) laser pulse. It has been found that the Br2 + product ion preferentially originates from the cis isomer rather than from trans. The Boltzmann-type isotropic low kinetic energy components of the Br+ and Br2 + product state distributions seem to be most likely from the unimolecular reactions of the vibrationally hot cationic ground state generated by the three-photon absorption at the photon energy below ∼38 000 cm-1. The highly anisotropic kinetic energy components of Br+ and Br2 + start to appear at the photon energy above ∼38 000 cm-1, where the Dn (n ≥ 1) - D0 transition is facilitated within the same ps laser pulse as the parent molecule is efficiently ionized by the two-photon absorption. The transition dipole moment of the D4 - D0 transition of the strongest oscillator strength has been theoretically predicted to be parallel to the C-Br bond or C=C bond axis for the trans or cis isomer, respectively. The fast anisotropic with the (β ∼ +2) component in the Br+ product distribution is thus likely from the trans isomer, whereas that of Br2 + (β ∼ -0.5) should be the consequence of the photodissociation of the cis isomer. The isomer-specific reactivity found here in the picosecond multiphoton excitation of 1,2-DBE provides a nice platform for the better understanding of the structure-reactivity relationship under the harsh condition of the strong or ultrashort optical field.
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Affiliation(s)
- Junggil Kim
- Department of Chemistry, KAIST, Daejeon 34141, Republic of Korea
| | - Sang Kyu Kim
- Department of Chemistry, KAIST, Daejeon 34141, Republic of Korea
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Balaganesh M, Song J, Kasai T, Lin KC. Photodissociation of CH 2BrCHBrC(O)Cl at 248 nm: probing Br 2 as the primary fragment using cavity ring-down spectroscopy. Phys Chem Chem Phys 2021; 23:22492-22500. [PMID: 34590099 DOI: 10.1039/d1cp02279b] [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
The photodissociation of 2,3-dibromopropionyl chloride (CH2BrCHBrC(O)Cl, 2,3-DBPC) at 248 nm was carried out to study Br2 as the primary molecular product in the B3Π+0u ← X1Σ+g transition using cavity ring-down absorption spectroscopy. The rotational spectra (v'' = 0-2) were acquired and assigned with the aid of spectral simulation. It is verified that the obtained Br2 fragment is attributed to the one-photon dissociation of 2,3-DBPC and is free from contributions of secondary reactions. The vibrational ratio of the Br2 population of v(0):v(1):v(2) is equal to 1:(0.58 ± 0.12):(0.23 ± 0.09), corresponding to the Boltzmann vibrational temperature of 623 ± 38 K. The quantum yield of Br2 eliminated from 2,3-DBPC is estimated to be 0.09 ± 0.04. The dissociation pathways of 2,3-DBPC and its potential energy surfaces were calculated using density functional theory. By employing the CCSD(T)//M062X/6-31+g(d,p) level of theory, transition state barriers and corresponding reaction energies were calculated for the Br, Cl, Br2, BrCl, HBr and HCl elimination channels. The unimolecular rate constant for Br2 elimination was determined to be 2.09 × 105 s-1 using Rice-Ramsperger-Kassel-Marcus (RRKM) theory, thus explaining the small quantum yield of the Br2 channel.
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Affiliation(s)
- Muthiah Balaganesh
- Department of Chemistry, National Taiwan Univeristy, Taipei 106, Taiwan.
| | - Joseph Song
- Department of Chemistry, Stony Brook University, 100 Nicolls Road, Stony Brook, New York 11794-3400, USA
| | - Toshio Kasai
- Department of Chemistry, National Taiwan Univeristy, Taipei 106, Taiwan. .,Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - King-Chuen Lin
- Department of Chemistry, National Taiwan Univeristy, Taipei 106, Taiwan. .,Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
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Lin KC, Muthiah B, Chang HP, Kasai T, Chang YP. Halogen-related photodissociation in atmosphere: characterisation of atomic halogen, molecular halogen, and hydrogen halide. INT REV PHYS CHEM 2020. [DOI: 10.1080/0144235x.2020.1822590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- King-Chuen Lin
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan
| | | | - Hsiu-Pu Chang
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Toshio Kasai
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
- Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
| | - Yuan-Pin Chang
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung, Taiwan
- Aerosol Science Research Center, National Sun Yat-sen University, Kaohsiung, Taiwan
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung, Taiwan
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Lin KC, Tsai PY. Molecular halogen elimination from halogen-containing compounds in the atmosphere. Phys Chem Chem Phys 2014; 16:7184-98. [PMID: 24622955 DOI: 10.1039/c3cp54828g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Atmospheric halogen chemistry has drawn much attention, because the halogen atom (X) playing a catalytic role may cause severe stratospheric ozone depletion. Atomic X elimination from X-containing hydrocarbons is recognized as the major primary dissociation process upon UV-light irradiation, whereas direct elimination of the X2 product has been seldom discussed or remained a controversial issue. This account is intended to review the detection of X2 primary products using cavity ring-down absorption spectroscopy in the photolysis at 248 nm of a variety of X-containing compounds, focusing on bromomethanes (CH2Br2, CF2Br2, CHBr2Cl, and CHBr3), dibromoethanes (1,1-C2H4Br2 and 1,2-C2H4Br2) and dibromoethylenes (1,1-C2H2Br2 and 1,2-C2H2Br2), diiodomethane (CH2I2), thionyl chloride (SOCl2), and sulfuryl chloride (SO2Cl2), along with a brief discussion on acyl bromides (BrCOCOBr and CH2BrCOBr). The optical spectra, quantum yields, and vibrational population distributions of the X2 fragments have been characterized, especially for Br2 and I2. With the aid of ab initio calculations of potential energies and rate constants, the detailed photodissociation mechanisms may be comprehended. Such studies are fundamentally important to gain insight into the dissociation dynamics and may also practically help to assess the halogen-related environmental variation.
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Affiliation(s)
- King-Chuen Lin
- Department of Chemistry, National Taiwan University, Taipei, and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan.
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Fan H, Tsai PY, Lin KC, Lin CW, Yan CY, Yang SW, Chang AHH. Molecular elimination of Br2 in photodissociation of CH2BrC(O)Br at 248 nm using cavity ring-down absorption spectroscopy. J Chem Phys 2012; 137:214304. [DOI: 10.1063/1.4767346] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Wu CC, Lin HC, Chang YB, Tsai PY, Yeh YY, Fan H, Lin KC, Francisco JS. Br2 molecular elimination in photolysis of (COBr)2 at 248 nm by using cavity ring-down absorption spectroscopy: A photodissociation channel being ignored. J Chem Phys 2011; 135:234308. [DOI: 10.1063/1.3664782] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Hua L, Lee WB, Chao MH, Zhang B, Lin KC. Elimination mechanisms of Br2+ and Br+ in photodissociation of 1,1- and 1,2-dibromoethylenes using velocity imaging technique. J Chem Phys 2011; 134:194312. [DOI: 10.1063/1.3584178] [Citation(s) in RCA: 11] [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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Chen SY, Tsai PY, Lin HC, Wu CC, Lin KC, Sun BJ, Chang AHH. I2 molecular elimination in single-photon dissociation of CH2I2 at 248 nm by using cavity ring-down absorption spectroscopy. J Chem Phys 2011; 134:034315. [DOI: 10.1063/1.3523571] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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Shi W, Staroverov VN, Lipson RH. Photodissociation of the geometric isomers of 1,2-dibromoethylene. J Chem Phys 2009; 131:154304. [DOI: 10.1063/1.3246824] [Citation(s) in RCA: 5] [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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Lee PC, Tsai PY, Hsiao MK, Lin KC, Huang CH, Chang AHH. Probing the Ignored Elimination Channel of Br2in the 248 nm Photodissociation of 1,1-Dibromoethylene by Cavity Ring-Down Absorption Spectroscopy. Chemphyschem 2009; 10:672-9. [DOI: 10.1002/cphc.200800665] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Lee HL, Lee PC, Tsai PY, Lin KC, Kuo HH, Chen PH, Chang AHH. Photodissociation of dibromoethanes at 248 nm: An ignored channel of Br[sub 2] elimination. J Chem Phys 2009; 130:184308. [DOI: 10.1063/1.3130768] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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