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Mao R, Wu D, Zhang Q, Chen Y. DC slice ion imaging of the ultraviolet photodissociation of 2-bromohexane. Chem Phys 2023. [DOI: 10.1016/j.chemphys.2022.111803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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2
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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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3
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Tsuru S, Fujikawa T, Stener M, Decleva P, Yagishita A. Theoretical study of ultrafast x-ray photoelectron diffraction from molecules undergoing photodissociation. J Chem Phys 2018; 148:124101. [DOI: 10.1063/1.5019878] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Affiliation(s)
- Shota Tsuru
- Graduate School of Science, Chiba University, Yayoi-cho 1-33, Inage, Chiba 263-8522, Japan
| | - Takashi Fujikawa
- Graduate School of Science, Chiba University, Yayoi-cho 1-33, Inage, Chiba 263-8522, Japan
| | - Mauro Stener
- Dipartimento di Scienze Chimiche, Università di Trieste, Via L. Giorgieri 1, I-34127 Trieste, Italy
| | - Piero Decleva
- Dipartimento di Scienze Chimiche, Università di Trieste, Via L. Giorgieri 1, I-34127 Trieste, Italy
| | - Akira Yagishita
- Photon Factory, Institute of Materials Structure Science, KEK, Oho1-1, Tsukuba, Ibaraki 305-0801, Japan
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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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Li Q, Zhu R, Lu J, Zhang X, Tang B. Vibrational excitations in chloromethyl radical formed by the photodissociation of chlorobromomethane. J Chem Phys 2014; 140:034303. [PMID: 25669375 DOI: 10.1063/1.4861672] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Using velocity map ion imaging, the photodissociation of chlorobromomethane (CH2BrCl) at 233-234 nm has been studied. The total translational energy distributions and the anisotropy parameters have been determined from the ion images of the photofragments Br ((2)P1/2) (denoted as Br(*)) and Br ((2)P3/2) (denoted as Br) for the dominant CH2BrCl + hv → CH2Cl + Br(*) and CH2BrCl + hv → CH2Cl + Br channels. Using an impulsive model invoking angular momentum conservation, the vibrational energy distributions of the chloromethyl radicals have been derived from the total translational energy distributions for the two channels. The study suggests that there are a number of vibrational modes of the chloromethyl radical to be excited in both of the two photodissociation channels. In the Br* channel, the CH2 s-stretch mode v1 has the most probability of excitation. While in the Br channel, the CH2 scissors mode ν2 is attributed to the highest peak of the vibrational energy curve of the chloromethyl radical. The results further imply that, following absorption of one UV photon of 234 nm, other vibrational modes besides v5 (C-Br stretch mode) are also excited in the parent molecule.
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Affiliation(s)
- Qianguang Li
- Department of Physics, Hubei Engineering University, Xiaogan City, Hubei Province 432000, People's Republic of China
| | - Rongshu Zhu
- Environmental Science and Engineering Research Center, Harbin Institute of Technology Shenzhen Graduate School, Shenzhen 518055, People's Republic of China
| | - Jinjun Lu
- Department of Physics, Hubei Engineering University, Xiaogan City, Hubei Province 432000, People's Republic of China
| | - Xiu Zhang
- Department of Physics, Hubei Engineering University, Xiaogan City, Hubei Province 432000, People's Republic of China
| | - Bifeng Tang
- Department of Physics, Hubei Engineering University, Xiaogan City, Hubei Province 432000, People's Republic of China
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Gu Z, Chen M, He C, Bai X, Mao R, Zhang Q, Chen Y. Using Ion‐velocity Map Imaging Technique to Study Photodissociation of 2‐Bromopentane. CHINESE J CHEM PHYS 2013. [DOI: 10.1063/1674-0068/26/05/493-497] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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7
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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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8
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Zhou DN, Mao R, Zhang LM, Zhang Q, Chen Y. Photodissociation of 2-Bromobutane at ∼265 nm by Ion-velocity Map Imaging Technique. CHINESE J CHEM PHYS 2012. [DOI: 10.1088/1674-0068/25/04/373-378] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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9
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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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10
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Zhou DN, Mao R, Zhang LM, Zhang Q, Chen Y. Photodissociation of 2-Bromobutane by Ion-velocity Map Imaging Technique. CHINESE J CHEM PHYS 2011. [DOI: 10.1088/1674-0068/24/06/647-652] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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11
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Photodissociation studies of cyclopentyl bromide at 234 and 266nm using velocity ion imaging technique. Chem Phys Lett 2011. [DOI: 10.1016/j.cplett.2011.06.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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12
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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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13
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Indulkar YN, Saha A, Upadhyaya HP, Kumar A, Waghmode SB, Naik PD, Bajaj PN. Photodissociation dynamics of 3-bromo-1,1,1-trifluoro-2-propanol and 2-(bromomethyl) hexafluoro-2-propanol at 234 nm: Resonance-enhanced multiphoton ionization detection of Br (2Pj). J Chem Phys 2011; 134:194313. [DOI: 10.1063/1.3591373] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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14
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Chichinin AI, Gericke KH, Kauczok S, Maul C. Imaging chemical reactions – 3D velocity mapping. INT REV PHYS CHEM 2009. [DOI: 10.1080/01442350903235045] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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15
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Kettwich SC, Paulson LO, Raston PL, Anderson DT. Photodissociation of Molecular Bromine in Solid H2 and D2: Spectroscopy of the Atomic Bromine Spin−Orbit Transition. J Phys Chem A 2008; 112:11153-8. [DOI: 10.1021/jp8029314] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Leif O. Paulson
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071
| | - Paul L. Raston
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071
| | - David T. Anderson
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071
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16
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Photodissociation study of 1,2-C2H4BrCl at 234 and 267nm by the ion-velocity imaging technique. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.05.098] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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17
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Tellinghuisen J. Equilibrium Constants from Spectrophotometric Data: Dimer Formation in Gaseous Br2. J Phys Chem A 2008; 112:5902-7. [DOI: 10.1021/jp8020358] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Joel Tellinghuisen
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235
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Wang Y, Zhang S, Wei Z, Zheng Q, Zhang B. Br(Pj2) atom formation dynamics in ultraviolet photodissociation of tert-butyl bromide and iso-butyl bromide. J Chem Phys 2006; 125:184307. [PMID: 17115752 DOI: 10.1063/1.2371033] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The photodissociation dynamics of tert-C(4)H(9)Br and iso-C(4)H(9)Br has been studied at 234 and 265 nm using two-dimensional velocity map imaging technique. The translational energy and angular distributions have been analyzed for Br, Br(*), and tert-C(4)H(9) radical. The energy distribution of Br atom in the photodissociation of tert-C(4)H(9)Br is found to consist of two Gaussian components. The two components are correlated to two independent reaction paths on the excited potential energy surfaces: (1) the high-energy component from the prompt dissociation along the C-Br stretching mode and (2) the low-energy component from the repulsive mode along the C-Br stretching, coupled with some bending motions. For the energy distribution of Br(*) atom in the photodissociation of tert-C(4)H(9)Br, a third multiphoton dissociative ionization channel is observed at 265 nm in addition to the two energy components corresponding to channels (1) and (2). The energy distributions of Br and Br(*) atoms in the photodissociation of iso-C(4)H(9)Br can be fitted using only one Gaussian function indicating a single formation channel. Relative quantum yields for Br((2)P(32)) at 234 and 265 nm in the photodissociation of tert-C(4)H(9)Br are measured to be 0.76 and 0.65, respectively. For iso-C(4)H(9)Br, the measured value is Phi(234 nm)(Br)=0.81. The contribution of bending modes to Br and Br(*) is much more obvious in the photodissociation of tert-C(4)H(9)Br than in iso-C(4)H(9)Br.
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Affiliation(s)
- Yanmei Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China
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Ji L, Tang Y, Zhu R, Wei Z, Zhang B. Photodissociation dynamics of allyl bromide at 234, 265, and 267 nm. J Chem Phys 2006; 125:164307. [PMID: 17092073 DOI: 10.1063/1.2360280] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The photodissociation dynamics of allyl bromide was investigated at 234, 265, and 267 nm. A two-dimensional photofragment ion velocity imaging technique coupled with a [2+1] resonance-enhanced multiphoton ionization scheme was utilized to obtain the angular and translational energy distributions of the nascent Br* (2P1/2) and Br (2P3/2) atoms. The Br fragments show a bimodal translational energy distribution, while the Br* fragments reveal one translational energy distribution. The vertical excited energies and the mixed electronic character of excited states were calculated at ab initio configuration interaction method. It is presumed that the high kinetic energy bromine atoms are attributed to the predissociation from 1(pipi*) or 1(pisigma*) state to the repulsive 1(nsigma*) state, and to the direct dissociation from 3(nsigma*) and 3(pisigma*) states, while the low kinetic energy bromine atoms stem from internal conversion from the lowest 3(pipi*) state to 3(pisigma*) state.
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Affiliation(s)
- Lei Ji
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China
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Plenge J, Nicolas C, Caster AG, Ahmed M, Leone SR. Two-color visible/vacuum ultraviolet photoelectron imaging dynamics of Br2. J Chem Phys 2006; 125:133315. [PMID: 17029468 DOI: 10.1063/1.2217375] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
An experimental two-color photoionization dynamics study of laser-excited Br2 molecules is presented, combining pulsed visible laser excitation and tunable vacuum ultraviolet (VUV) synchrotron radiation with photoelectron imaging. The X 1Sigmag + -B 3Pi0+u transition in Br2 is excited at 527 nm corresponding predominantly to excitation of the v' = 28 vibrational level in the B 3Pi0+u state. Tunable VUV undulator radiation in the energy range of 8.40-10.15 eV is subsequently used to ionize the excited molecules to the X 2Pi32,12 state of the ion, and the ionic ground state is probed by photoelectron imaging. Similar experiments are performed using single-photon synchrotron ionization in the photon energy range of 10.75-12.50 eV without any laser excitation. Photoelectron kinetic energy distributions are extracted from the photoelectron images. In the case of two-color photoionization using resonant excitation of the intermediate B 3Pi0+u state, a broad distribution of photoelectron kinetic energies is observed, and in some cases even a bimodal distribution, which depends on the VUV photon energy. In contrast, for single-photon ionization, a single nearly Gaussian-shaped distribution is observed, which shifts to higher energy with photon energy. Simulated spectra based on Franck-Condon factors for the transitions Br2(X 1Sigmag+, v" = 0)-Br2 +(X 2Pi12,32, v+) and Br2(B 3Pi0+u, v' = 28)-Br2 +(X 2Pi12,32, v+) are generated. Comparison of these calculated spectra with the measured images suggests that the differences in the kinetic energy distributions for the two ionization processes reflect the different extensions of the vibrational wave functions in the v" = 0 electronic ground state (X 1Sigmag+) versus the electronically and vibrationally excited state (B 3Pi0+u, v' = 28).
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Affiliation(s)
- Jürgen Plenge
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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Wang Y, Zhang S, Zheng Q, Zhang B. C–Br bond fission dynamics in ultraviolet photodissociation of 1,2-dibromoethane. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.03.048] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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22
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Liu Y, Lau KC, Butler LJ. Photodissociation of Cyclobutyl Bromide at 234 nm Studied Using Velocity Map Imaging. J Phys Chem A 2006; 110:5379-85. [PMID: 16623465 DOI: 10.1021/jp056255m] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
This study investigates the 234 nm photodissociation dynamics of cyclobutyl bromide using a two-dimensional photofragment velocity imaging technique. The spin-orbit ground- and excited-state Br(2P) atoms are state-selectively detected via [2+1] resonance enhanced multiphoton ionization (REMPI), whereas the cyclobutyl radicals are ionized using 157 nm laser light. The Br(2P(3/2)) and the Br(2P(1/2)) atoms and their c-C4H7 radical cofragments evidence a single-peaked, Gaussian-shaped translational energy distribution ranging from approximately 14 to approximately 39 kcal/mol and angular distributions with significant parallel character. The Br(2P(1/2))/ Br(2P(3/2)) spin-orbit branching ratio is determined to be 0.11 +/- 0.07 by momentum match between the Br(2P) photofragments and the recoiling c-C4H7 fragments, assuming a uniform photoionization probability of the c-C4H7 radicals with an internal energy range of 10-35 kcal/mol. The REMPI line strength ratio for the detection of Br(2P(3/2)) and Br(2P(1/2)) atoms at 233.681 and 234.021 nm, respectively, is therefore derived to be 0.10 +/- 0.07. The measured recoil kinetic energies of the c-C4H7 radicals, and the resulting distribution of internal energies, indicates some of the radicals are formed with total internal energies above the barrier to isomerization and subsequent dissociation, but our analysis indicates they may be stable due to the substantial fraction of the internal energy which is partitioned to rotational energy of the radicals.
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Affiliation(s)
- Yi Liu
- James Franck Institute and Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA
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Tang Y, Ji L, Zhu R, Wei Z, Zhang B. Photodissociation study of 1,3-dibromopropane at 234 nm via an ion velocity imaging technique. J Phys Chem A 2006; 109:11123-6. [PMID: 16331895 DOI: 10.1021/jp0537097] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The photodissociation of 1,3-dibromopropane has been studied at 234 nm using a 2D photofragment ion velocity imaging technique coupled with a [2 + 1] resonance-enhanced multiphoton ionization scheme. The velocity distributions for the Br (2P1/2) (denoted Br) and Br (2P3/2) (denoted Br) fragments are determined, and each can be fitted by a narrow single-peaked Gaussian curve, suggesting that bromine fragments are generated as a result of direct dissociation via repulsive potential energy surfaces. The recoil anisotropies were measured to be beta = 0.80 for Br and 1.31 for Br, and the product relative quantum yields at 234 nm is Phi234 nm(Br) = 0.21.
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Affiliation(s)
- Ying Tang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China
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Ashfold MNR, Nahler NH, Orr-Ewing AJ, Vieuxmaire OPJ, Toomes RL, Kitsopoulos TN, Garcia IA, Chestakov DA, Wu SM, Parker DH. Imaging the dynamics of gas phase reactions. Phys Chem Chem Phys 2006; 8:26-53. [PMID: 16482242 DOI: 10.1039/b509304j] [Citation(s) in RCA: 240] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ion imaging methods are making ever greater impact on studies of gas phase molecular reaction dynamics. This article traces the evolution of the technique, highlights some of the more important breakthroughs with regards to improving image resolution and in image processing and analysis methods, and then proceeds to illustrate some of the many applications to which the technique is now being applied--most notably in studies of molecular photodissociation and of bimolecular reaction dynamics.
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Tang Y, Ji L, Zhu R, Wei Z, Zhang B. Photodissociation Study of Ethyl Bromide in the Ultraviolet Range by the Ion-Velocity Imaging Technique. Chemphyschem 2005; 6:2137-44. [PMID: 16208756 DOI: 10.1002/cphc.200500246] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The photodissociation of ethyl bromide has been studied in the wavelength range of 231-267 nm by means of the ion velocity imaging technique coupled with a [2+1] resonance-enhanced multiphoton ionization (REMPI) scheme. The velocity distributions for the Br ((2)P(1/2)) (denoted Br*) and Br ((2)P(3/2)) (denoted Br) fragments are determined, and each can be well-fitted by a narrow single-peaked Gaussian curve, which suggests that the bromine fragments are generated as a result of direct dissociation via repulsive potential-energy surfaces (PES). The recoil anisotropy results show that beta(Br) and beta(Br*) decrease with the wavelength, and the angular distributions of Br* suggest a typical parallel transition. The product relative quantum yields at two different wavelengths are Phi(234nm)(Br*)=0.17 and Phi(267nm)(Br*)=0.31. The relative fractions of each potential surface for the bromine fragments' production at 234 and 267 nm reveal the existence of a curve crossing between the (3)Q(0) and (1)Q(1) potential surfaces, and the probability of curve crossing decreases with the laser wavelength. The symmetry reduction of C(2)H(5)Br from C(3v) to C(s) invokes a nonadiabatic coupling between the (3)Q(0) and (1)Q(1) states, and with higher energy photons, the probability that crossing will take place increases.
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Affiliation(s)
- Ying Tang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China
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Tang B, Zhang B. Photodissociation pathways and dissociation energy of C–Br bond of n-C4H9Br determined using velocity map imaging. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.06.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Zhu R, Tang B, Ji L, Tang Y, Zhang B. Measurement of photolysis branching ratios of 2-bromopropane at 234 and 267nm. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.02.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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29
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Tang B, Zhu R, Tang Y, Ji L, Zhang B. Photodissociation dynamics of C2H5Br and n-C3H7Br in UV region. Chem Phys 2004. [DOI: 10.1016/j.chemphys.2004.05.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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30
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Tang Y, Ji L, Tang B, Zhu R, Zhang S, Zhang B. Studies on photodissociation of alkyl bromides at 234 and 267 nm. Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2004.06.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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31
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Photodissociation of bromobenzene at 267 and 234 nm: experimental and theoretical investigation of the photodissociation mechanism. Chem Phys Lett 2003. [DOI: 10.1016/j.cplett.2003.10.049] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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32
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Asano Y, Yabushita S. Theoretical study of nonadiabatic transitions in the photodissociation of Cl2 and Br2. Chem Phys Lett 2003. [DOI: 10.1016/s0009-2614(03)00432-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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