Multi-photon dissociation dynamics of Freon 114B2 under UV radiation by femtosecond laser pulse

CORC > 武汉物理与数学研究所 > 中国科学院武汉物理与数学研究所 > 原子分子光物理研究部

	Multi-photon dissociation dynamics of Freon 114B2 under UV radiation by femtosecond laser pulse
	Liu Yu-Zhu 1,2; Deng Xu-Lan 3; Li Shuai 3; Guan Yue 1,2; Li Jing 1,2; Long Jin-You 3; Zhang Bing 3
刊名	ACTA PHYSICA SINICA
	2016-10-05
卷号	65 期号:19
关键词	Freon114b2 photodissociation velocity map imaging femtosecond ultrafast
英文摘要	The ozone layer which absorbs harmful solar UV radiation is a necessary umbrella for human beings and biosphere. A large amount of alkyl halide including freon exhausted by human into the atmosphere poses a great threat to the ozone layer. Freon dissociates into the product of halogen radical, like Br and Cl, induced by UV sunlight radiation, which is found to be the main culprit for the destruction of atmospheric ozone. In this paper, time-of-flight (TOF) mass spectrometry and velocity map imaging technique are employed for investigating the multiphoton dissociation dynamics of Freon F114B2 (C2F4Br2) induced by femtosecond UV radiation at 267 nm. Fragment mass spectra of C2F4Br2 under UV radiation at 266 nm are obtained by TOF mass spectrometry. Three daughter ions C2F4Br+, C2F4+ and CF2Br+ are discovered together with the parent ions C2F4Br2+. And three corresponding photodissociation mechanisms are concluded as follows: 1) C2F4Br2+ -> C2F4Br+ +Br with single C-Br bond breaking and direct production of Br radical; 2) C2F4Br2+ -> C2F4++2Br with double C-Br bonds breaking and production of two Br radical; 3) C2F4Br2+ -> CF2Br+ +CF2Br with C-C bond breaking. Velocity map images of the strongest daughter ion C2F4B+ with C-Br breaking are measured by imaging apparatus. The kinetic energy distribution of C2F4B+ ions is obtained from the measured velocity map images. And it can be well fitted by three Gaussian curves which describe normal distribution. It indicates that the production of the fragment C2F4B+ stems from three different dissociation channels. Additional photodissociation dynamics is obtained by analyzing the angular distribution of the measured image. The values of anisotropy parameter beta are measured to be 0.1 (for the low energy channel), 0.8 (for the middle energy channel) and 1.4 (for the high energy channel) for the fragment C2F4B+ , respectively. The ratios of parallel transition to perpendicular transition are determined for three different channels. In addition, density functional theory calculations are also performed for further analysis and discussion. The optimized geometries of ground state and ionic state of C2F4Br2 are obtained and compared at the level of B3LYP/6-311G++(d, p). The calculated information about ionic states, including energy level and oscillator strength for the ionic excited states, are given.
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Physics, Multidisciplinary
研究领域[WOS]	Physics
关键词[WOS]	MOLECULAR-OXYGEN ; PHOTOELECTRON ; OZONE
收录类别	SCI
语种	英语
WOS记录号	WOS:000387141500006
内容类型	期刊论文
源URL	[http://ir.wipm.ac.cn/handle/112942/9964]
专题	武汉物理与数学研究所_原子分子光物理研究部
作者单位	1.Nanjing Univ Informat Sci & Technol, Sch Phys & Optoelect Engn, Nanjing 210044, Jiangsu, Peoples R China 2.Jiangsu Collaborat Innovat Ctr Atmospher Environm, Nanjing 210044, Jiangsu, Peoples R China 3.Chinese Acad Sci, Wuhan Inst Phys & Math, State Key Lab Magnet Resonance & Atom & Mol Phys, Wuhan 430074, Peoples R China
推荐引用方式 GB/T 7714	Liu Yu-Zhu,Deng Xu-Lan,Li Shuai,et al. Multi-photon dissociation dynamics of Freon 114B2 under UV radiation by femtosecond laser pulse[J]. ACTA PHYSICA SINICA,2016,65(19).
APA	Liu Yu-Zhu.,Deng Xu-Lan.,Li Shuai.,Guan Yue.,Li Jing.,...&Zhang Bing.(2016).Multi-photon dissociation dynamics of Freon 114B2 under UV radiation by femtosecond laser pulse.ACTA PHYSICA SINICA,65(19).
MLA	Liu Yu-Zhu,et al."Multi-photon dissociation dynamics of Freon 114B2 under UV radiation by femtosecond laser pulse".ACTA PHYSICA SINICA 65.19(2016).