物理化学学报 >> 2015, Vol. 31 >> Issue (9): 1655-1661.doi: 10.3866/PKU.WHXB201506291

热力学,动力学和结构化学 上一篇    下一篇

邻二氯苯激发态动力学

李晓营1,王利2,*(),王艳秋3,宋哲1,刘本康3,*()   

  1. 1 辽宁师范大学物理与电子学院,辽宁大连116029
    2 大连民族大学物理与材料工程学院,辽宁大连116600
    3 中国科学院大连化学物理研究所,分子反应动力学国家重点实验室,辽宁大连116023
  • 收稿日期:2015-04-07 发布日期:2015-09-06
  • 通讯作者: 王利,刘本康 E-mail:liwangye@dlnu.edu.cn;liubk@dicp.ac.cn
  • 基金资助:
    国家自然科学基金(21303199)

Dynamics of Excited o-Dichlorobenzene

Xiao-Ying. LI1,Li. WANG2,*(),Yan-Qiu. WANG3,Zhe. SONG1,Ben-Kang. LIU3,*()   

  1. 1 School of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029, Liaoning Province, P. R. China
    2 College of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600, Liaoning Province, P. R. China
    3 State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning Province, P. R. China
  • Received:2015-04-07 Published:2015-09-06
  • Contact: Li. WANG,Ben-Kang. LIU E-mail:liwangye@dlnu.edu.cn;liubk@dicp.ac.cn
  • Supported by:
    the National Natural Science Foundation of China(21303199)

摘要:

利用飞秒分辨的激光泵浦-探测技术结合飞行时间质谱和光电子速度成像方法研究了邻二氯苯第一电子单重激发态(S1)的超快动力学.邻二氯苯的S1态振动基态寿命为(651 ± 10) ps,对应于S1振动基态向三重态的系间窜越过程.邻二氯苯S1的高振动激发9a218a2对应两个衰减通道,其中寿命为(458 ± 12) fs的超快过程对应于由处于振动激发的S1向高振动激发的基态(S0)发生的内转换过程,而寿命为(90 ± 10) ps过程则对应由S1态向三重态(T1)的系间窜越过程,电离产生的光电子能谱中长寿命的谱峰可能与系间窜越过程有关. S1态高振动态的旋轨耦合程度比低振动态的更强,导致系间窜越过程更快.

关键词: 邻二氯苯, 振动激发, 光电子成像, 光电子能谱

Abstract:

The dynamics of the first excited singlet electronic state (S1) of o-dichlorobenzene was investigated in real time by the femtosecond pump-probe method combined with time-of-flight mass spectroscopy and the photoelectron velocity mapping technique. The lifetime of the S1 vibrational ground state was determined experimentally to be (651 ± 10) ps, corresponding to the intersystem crossing process from the S1 state to the triplet state. Two decay channels were found in the S1 vibrationally excited mode 9a218a2. The fast process (lifetime constant (458 ± 12) fs) is because of the internal conversion from the S1 vibrationally excited mode to the highly vibrationally excited ground state (S0). The slow process (lifetime constant (90 ± 10) ps) is attributed to the intersystem crossing process from the S1 state to the triplet state (T1). Photoelectrons with long lifetime characteristics in the spectrum might be connected with the intersystem crossing process. Enhanced spinorbital coupling in the S1 highly vibrationally excited state accelerates the intersystem crossing process.

Key words: o-Dichlorobenzene, Vibrational excitation, Photoelectron imaging, Photoelectron kinetic energy spectrum

MSC2000: 

  • O644