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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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Nakamura M, Chang HP, Lin KC, Kasai T, Che DC, Palazzetti F, Aquilanti V. Stereodynamic Imaging of Bromine Atomic Photofragments Eliminated from 1-Bromo-2-methylbutane Oriented via Hexapole State Selector. J Phys Chem A 2019; 123:6635-6644. [PMID: 31177785 DOI: 10.1021/acs.jpca.9b04048] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Both single-laser and two-laser experiments were conducted to look into the ion-imaging of Br*(2P1/2) and Br(2P3/2) photofragmented from 1-bromo-2-methylbutane in the range 232-240 nm via a detection scheme of (2+1) resonance-enhanced multiphoton ionization. The angular analysis of these photofragment distributions yields the anisotropy parameter β = 1.88 ± 0.06 for the Br* excited state which arises from a parallel transition, while β = 0.63 ± 0.09 for the Br ground state indicates the contribution from both a perpendicular transition and a non-adiabatic transition. When a hexapole coupled with an orienting field was implemented, the parent molecules are spatially oriented to yield an orientation efficiency |⟨cos θ⟩| of 0.15. Besides the χ angle between the recoil velocity v and the transition dipole moment μ, orienting molecules allows for the evaluation of the angle α between v and the permanent molecular dipole moment d. The angular analysis of Br* photofragment distribution yields χ = 11.5° and α in the range from 160° to 180° with weak dependency. In the two-laser experiments, the angular anisotropy of Br photofragment distribution was found to be smaller (0.38 ± 0.10) when the photolysis wavelength was red-shifted to 240 nm, suggesting the increasing contributions from perpendicular transitions.
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Affiliation(s)
- Masaaki Nakamura
- Department of Chemistry , National Taiwan University , Taipei 10617 , Taiwan
| | - Hsiu-Pu Chang
- Department of Chemistry , National Taiwan University , Taipei 10617 , Taiwan
| | - King-Chuen Lin
- Department of Chemistry , National Taiwan University , Taipei 10617 , Taiwan.,Institute of Atomic and Molecular Sciences , Academia Sinica , Taipei 10617 , Taiwan
| | - Toshio Kasai
- Department of Chemistry , National Taiwan University , Taipei 10617 , Taiwan.,Institute of Scientific and Industrial Research , Osaka University , Ibaraki, Osaka 567-0047 , Japan
| | - Dock-Chil Che
- Department of Chemistry, Graduate School of Science , Osaka University , Toyonaka, Osaka 560-0043 , Japan
| | - Federico Palazzetti
- Dipartimento di Chimica, Biologia e Biotecnologie , Università di Perugia , 06123 Perugia , Italy
| | - Vincenzo Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie , Università di Perugia , 06123 Perugia , Italy.,Istituto di Struttura della Materia , Consiglio Nazionale delle Ricerche , 00016 Rome , Italy
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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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Zhong Z, Zeng T, Xie K, Zhang C, Chen J, Bi Y, Zhao X. Elevation of 4-hydroxynonenal and malondialdehyde modified protein levels in cerebral cortex with cognitive dysfunction in rats exposed to 1-bromopropane. Toxicology 2013; 306:16-23. [PMID: 23395825 DOI: 10.1016/j.tox.2013.01.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2012] [Revised: 01/26/2013] [Accepted: 01/29/2013] [Indexed: 11/16/2022]
Abstract
1-Bromopropane (1-BP), an alternative to ozone-depleting solvents (ODS), exhibits central nervous system (CNS) toxicity in animals and humans. This study was designed to relate CNS damage by Morris water maze (MWM) test and oxidative stress to 1-BP exposure in the rat. Male Wistar rats were randomly divided into 4 groups (n=10), and treated with 0, 200, 400 and 800 mg/kgbw 1-BP for consecutive 12 days, respectively. From day 8 to day 12 of the experiment, MWM test was employed to assess the cognitive function of rats. The cerebral cortex of rats was obtained immediately following the 24h after MWM test conclusion. Glutathione (GSH), oxidized glutathione (GSSG) and total thiol (total-SH) content, GSH reductase (GR) and GSH peroxidase (GSH-Px) activities, malondialdehyde (MDA) level, as well as 4-hydroxynonenal (4-HNE) and MDA modified proteins in homogenates of cerebral cortex were measured. The obtained results showed that 1-BP led to cognitive dysfunction of rats, which was evidenced by delayed escape latency time and swimming distances in MWM performance. GSH and total-SH content, GSH/GSSG ratio, GR activity significantly decreased in cerebral cortex of rats, coupling with the increase of MDA level. 4-HNE and MDA modified protein levels obviously elevated after 1-BP exposure. GSH-Px activities in cerebral cortex of rats also increased. These data suggested that 1-BP resulted in enhanced lipid peroxidation of brain, which might play an important role in CNS damage induced by 1-BP.
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Affiliation(s)
- Zhixia Zhong
- Institute of Toxicology, School of Public Health, Shandong University, Jinan, Shandong Province 250012, China
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Mao R, Zhang Q, Zang J, He C, Chen M, Chen Y. Multiphoton dissociative ionization of tert-pentyl bromide near 265 nm. J Chem Phys 2011; 135:244302. [PMID: 22225151 DOI: 10.1063/1.3671368] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report on the photodissociation dynamics of tert-pentyl bromide near 265 nm investigated by time-sliced velocity map imaging. The speed and angular distributions have been analyzed for both the ground-state Br((2)P(3∕2)) atom (denoted Br) and the spin-orbit excited-state Br((2)P(1∕2)) atom (denoted Br*). The speed distributions of Br and Br* atoms are all found to consist of three Gaussian components, which correlate to three independent dissociation pathways on the excited potential energy surfaces: (1) the high translational energy (E(T)) component from the prompt dissociation along the C-Br stretching mode, (2) the middle E(T) component from the repulsive mode along the C-Br stretching coupled with some bending motions, and (3) the low E(T) component from the repulsive mode along the C-Br stretching coupled with more bending motions. More interestingly, we have also observed the tert-C(5)H(11)(+) ions in 263-267 nm. The near-zero kinetic energy distributions extracted from the three tert-C(5)H(11)(+) images near 265 nm show the typical characteristics that are attributable to multiphoton dissociative ionization, suggesting the existence of a neutral superexcited state of the parent tert-pentyl bromide molecule. The contribution of bromine atoms formed in this dissociative ionization channel adds in the total relative distribution of low E(T) component in the Br*(Br) formation channel, which reasonably explains the abnormal distributions observed in between the middle and low E(T) components in the Br*(Br) formation channel.
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Affiliation(s)
- Rui Mao
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, People's Republic of China
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Hua L, Shen H, Hu C, Zhang B. Photoelectron imaging of atomic chlorine and bromine following photolysis of CH2BrCl. J Chem Phys 2008; 129:244308. [DOI: 10.1063/1.3047756] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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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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Wang Y, Zhang S, Wei Z, Zhang B. Velocity Map Imaging of Dissociative Ionization and Coulomb Explosion of CH3I Induced by a Femtosecond Laser. J Phys Chem A 2008; 112:3846-51. [DOI: 10.1021/jp711032z] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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, and Graduate School of the Chinese Academy of Sciences, Beijing 100039, People's Republic of China
| | - Song Zhang
- 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, and Graduate School of the Chinese Academy of Sciences, Beijing 100039, People's Republic of China
| | - Zhengrong Wei
- 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, and Graduate School of the Chinese Academy of Sciences, Beijing 100039, People's Republic of China
| | - Bing Zhang
- 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, and Graduate School of the Chinese Academy of Sciences, Beijing 100039, People's Republic of China
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Kaziannis S, Kosmidis C. Comparative Study of Multielectron Ionization of Alkyl Halides Induced by Picosecond Laser Irradiation. J Phys Chem A 2007; 111:2839-51. [PMID: 17388396 DOI: 10.1021/jp068300b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The interaction of C2H5X, 1-C3H7X, 1-C4H9X, where X = I, Br, Cl, with strong (1 x 10(13)-1.2 x 10(14) W/cm2) 35 ps laser pulses at 1064 nm is studied by means of time-of-flight mass spectrometry. The multielectron ionization following the C-X bond elongation has been verified for the studied molecules. By combination of the intensity dependence of the ion yields, the estimated kinetic energies of the released fragment ions, and their angular distributions, we have identified the different dissociation channels of the transient multiply charged parent ions. From the dependence on the laser intensity of the ratio of the doubly charged halogen ions to the singly charged ones, it is concluded that the molecular coupling with the laser field increases with the molecular size.
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Affiliation(s)
- S Kaziannis
- Department of Physics, University of Ioannina, 45110 Ioannina, Greece
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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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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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