Excited-state dynamics of m-dichlorobezene in ultrashort laser pulses

doi:10.7498/aps.66.157801

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

	Excited-state dynamics of m-dichlorobezene in ultrashort laser pulses
	Shen Huan 2,3; Hu Chun-Long 1; Deng Xu-Lan 1
刊名	ACTA PHYSICA SINICA
	2017-08-05
卷号	66 期号:15
关键词	Femtosecond Time-resolved Time-of-flight Mass Spectroscopy M-dichlorobenzene Excitedstate Dynamics
DOI	10.7498/aps.66.157801
文献子类	Article
英文摘要	The excited state dynamics of aromatic hydrocarbon has attracted a great deal of attention due to its important role in photophysics and atmosphere chemistry. With the benefit of ultra-short laser pulses, the ultrafast phenomenon can be studied in a time resolved way. In the present work, m-dichlorobenzene, a typical model of aromatic hydrocarbon, is investigated by the femtosecond time resolved time-of-flight mass spectroscopy. In order to reveal its excited state dynamics, m-dichlorobenzene is pumped to the excited state after absorbing one 200/267 nm photon, and then ionized by absorbing 800 nm photons. Time resolved mass spectra are recorded with time of flight. At 200 nm, m -dichlorobenzene is excited to a (pi, pi ) state. Three decay components are observed in the transient profiles of m -dichlorobenzene ions, which correspond to three competition channels in the excited states. The first channel is an ultrafast dissociation process via a repulsive state with (n, sigma) or (pi, sigma) character, and the lifetime is (0.1 5 +/- 0.01) ps. The second channel is an internal conversion process from the populated excited state to the hot ground state, and the lifetime of the redistribution of the internal vibration in the hot ground state is (4.9 4 +/- 0.08) ps. The third channel is an intersystem crossing process to the triplet state, and the lifetime is (110.0 9 +/- 4.33) ps. Moreover, the transient profiles of C6H4 Cl+/C6H4+ display similar decay tendencies to the transient profile of parent ion, except that longer lifetime constants ((127.38 +/- 29.29) ps for C6H4Cl+, and (123.7 6 +/- 3 7.12) ps for C6H4+, respectively) are observed. It is likely that the fragment ions result from the dissociative ionization of the parent molecule. At 267 nm, m -dichlorobenzene is excited to the first excited state with (n, sigma) character. Only C 6 H 4 Cl + 2 and C 6 H 4 Cl + are observed in the two-color mass spectrum. A slow decay component (similar to (1.0 6 +/- 0.05) ns) is obtained for both the parent ion and the fragment ion. It is attributed to an intersystem crossing process from the first excited state S 1 to the triplet state T 1. Furthermore, the transient profile of C6H4Cl+ displays other decay components, i.e., (2.4 8 +/- 0.09) ps, in addition to the slow decay component. This fast decay process can be attributed to an internal conversion process from the populated excited states to the hot ground states. The present study provides a more in-depth understanding of the ultrafast excited state dynamics of m -dichlorobenzene.
WOS关键词	PHOTODISSOCIATION DYNAMICS ; DISSOCIATIVE IONIZATION ; INTERNAL-CONVERSION ; P-CHLOROTOLUENE ; PHOTOELECTRON ; SPECTROSCOPY ; MOLECULES ; RATES ; IONS ; NM
WOS研究方向	Physics
语种	英语
WOS记录号	WOS:000410775700029
资助机构	National Natural Science Foundation of China(21403080) ; National Natural Science Foundation of China(21403080) ; National Natural Science Foundation of China(21403080) ; National Natural Science Foundation of China(21403080)
内容类型	期刊论文
源URL	[http://ir.wipm.ac.cn/handle/112942/11414]
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.Chinese Acad Sci, Wuhan Inst Phys & Math, State Key Lab Magnet Resonance & Atom & Mol Phys, Wuhan 430071, Hubei, Peoples R China 2.Huazhong Agr Univ, Inst Appl Phys, Wuhan 430070, Hubei, Peoples R China 3.Huazhong Agr Univ, Coll Sci, Wuhan 430070, Hubei, Peoples R China
推荐引用方式 GB/T 7714	Shen Huan,Hu Chun-Long,Deng Xu-Lan. Excited-state dynamics of m-dichlorobezene in ultrashort laser pulses[J]. ACTA PHYSICA SINICA,2017,66(15).
APA	Shen Huan,Hu Chun-Long,&Deng Xu-Lan.(2017).Excited-state dynamics of m-dichlorobezene in ultrashort laser pulses.ACTA PHYSICA SINICA,66(15).
MLA	Shen Huan,et al."Excited-state dynamics of m-dichlorobezene in ultrashort laser pulses".ACTA PHYSICA SINICA 66.15(2017).