Photofragment translational spectroscopy at 304 nm from C-H symmetric stretch excited CH_3I [v_1 = 1]  

作　　者：ZHOU ZhiMin HU LiLi DONG ChangWu ZHANG LiJuan LIU Sheng DU YiKui CHENG Min ZHU QiHe 

机构地区：[1]National Laboratory of Molecular Sciences [2]State Key Laboratory of Molecular Reaction Dynamics [3]Institute of Chemistry,Chinese Academy of Sciences

出　　处：《Science China Chemistry》2014年第6期902-910,共9页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China(21203207 and 21173236)

摘　　要：The 304 nm photodissociation of the C-H symmetric stretch excited CH3I[v1=1,v2=0](v1 denotes the C-H symmetric stretch mode,and v2 denotes the umbrella mode)is studied with our simple photofragment translational spectrometer.An IR laser is used to excite the ground state CH3I[0,0]to the C-H symmetric stretch excited CH3I[1,0].With IR laser OFF and ON,the fractions of photofragments CH3(ν1,ν2)from the 304 nm photodissociation of CH3I[1,0]have been determined through the photofragment translational spectra(PTS)from measuring I and I*and also through the PTS from measuring CH3(0,0)(1,0)(0,1)and(1,1).The experimental results show that the C-H symmetric stretch vibration(v1=1)in parent molecules is about 66%retained in the photofragments in the I channel,but only 24%in the I*channel.The populations of photofragments CH3(0,2)and(0,3)are higher than CH3(0,0)and(0,1),showing strong inverted population both in I and I*channels.The 304 nm photodissociation of the C-H symmetric stretch excited CH3I[v1=1,v2=0]（v1 denotes the C-H symmetric stretch mode,and v2 denotes the umbrella mode）is studied with our simple photofragment translational spectrometer.An IR laser is used to excite the ground state CH3I[0,0]to the C-H symmetric stretch excited CH3I[1,0].With IR laser OFF and ON,the fractions of photofragments CH3（ν1,ν2）from the 304 nm photodissociation of CH3I[1,0]have been determined through the photofragment translational spectra（PTS）from measuring I and I＊and also through the PTS from measuring CH3（0,0）（1,0）（0,1）and（1,1）.The experimental results show that the C-H symmetric stretch vibration（v1=1）in parent molecules is about 66%retained in the photofragments in the I channel,but only 24%in the I＊channel.The populations of photofragments CH3（0,2）and（0,3）are higher than CH3（0,0）and（0,1）,showing strong inverted population both in I and I＊channels.

关 键 词：PHOTODISSOCIATION methyl iodide excited vibrational state photofragment translational spectrum（PTS） 

分 类 号：O641.1[理学—物理化学]