Investigation of ultrafast excited-state dynamics of 3-furfural  

3-糠醛的激发态超快动力学研究

作　　者：Wenping Wu Yuhuan Tian Zhigang He Dongyuan Yang Guorong Wu Xueming Yang 吴文平;田宇欢;贺志刚;杨栋元;吴国荣;杨学明(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,大连116023;中国科学院大学,北京100049;南方科技大学理学院化学系,深圳518055)

机构地区：[1]State Key Laboratory of Molecular Reaction Dynamics,Dalian Institute of Chemical Physics,Dalian 116023,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]Department of Chemistry,Collge of Science,Southern University of Science and Technology,Shenzhen 518055,China

出　　处：《Chinese Journal of Chemical Physics》2024年第6期893-900,I0037-I0040,I0044,共13页化学物理学报(英文)

基　　金：supported by the National Natural Science Foundation of China(No.22203095,No.22103087,and No.22288201);the State Key Laboratory of Molecular Reaction Dynamics(SKLMRDZ202406);the Chinese Academy of Sciences(GJJSTD20220001).

摘　　要：3-Furfural(C_(5)H_(4)O_(2))is a furan(C_(4)H_(4)O)derivative compound formed by replacing the hydrogen(H)atom at the ring 3-position with the aldehyde(CHO)group substituent.In this work,we intend to investigate the ultrafast decay dynamics of electronically excited 3-furfural using the femtosecond time-resolved photoelectron imaging technique.At pump wavelengths of 259.5,238.6 and 218.311m,two alternative decay mechanisms for the S_(2)(^(1)ππ*)state are tentatively proposed and discussed.Specifically,we prefer to suggest that a fraction of the initially prepared wavepacket in the S_(2)(^(1)ππ*)state is likely to undergo the subpicosecond relaxation via the S_(1)(^(1)nπ*)state.Presumably the lower lying T_(2)(^(3)ππ*)state is subsequently populated on a∼4 ps timescale via intersystem crossing from the minimum of the S_(1)(^(1)nπ*)state surface.The relaxation of the T_(2)(^(3)ππ*)state is sensitive to its vibrational excess energy and the value of its lifetime is 1.6±0.2 ns,280±30 ps and 50±10 ps for pump wavelengths of 259.5,238.6 and 218.3 m,respectively.3-糠醛分子是呋喃分子的一个醛基取代衍生物,其呋喃环上3号位的氢原子被醛基所取代.本文试图利用飞秒时间分辨光电子成像的实验方法研究3-糠醛分子S_(2)(^(1)ππ*)态的超快衰变动力学.在259.5,238.6和218.3 nm的泵浦激发波长下,讨论了两种可能的S_(2)(^(1)ππ*)态衰变机制.具体而言,暂时更倾向于以下机制.一部分S_(2)(^(1)ππ*)态上的波包经历了亚皮秒的弛豫过程布居到了S_(1)(^(1)nπ*)态,随后在大概4 ps时间尺度下发生了由S_(1)(^(1)nπ*)态到T_(2)(^(3)ππ*)态的系间窜越.而T_(2)(^(3)ππ*)态的进一步衰变过程与其振动能量密切相关.对于259.5,238.6和218.3 nm初始激发波长,T_(2)(^(3)ππ*)态的寿命分别为1.6±0.2 ns,280±30 ps和50±10 ps.

关 键 词：Femtosecond time-resolved Photoelectron imaging Ultrafast decay dynamics 

分 类 号：O56[理学—原子与分子物理]