飞秒时间分辨质谱方法研究CF_3I光电离动力学  

Studies of Photoionization of CF_3I by Femtosecond Time-resolved Mass Spectrometry

作　　者：尹淑慧[1] 刘红平[1] 张建阳[1] 姜波[1] 王利[1] 沙国河[1] 楼南泉[1] 

机构地区：[1]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

出　　处：《Chinese Journal of Chemical Physics》2003年第1期3-8,共6页化学物理学报（英文）

基　　金：国家自然科学基金 (2 98330 802 995 30 0 1)资助项目

摘　　要：利用飞秒双色泵浦 探测 (pump probe)飞行时间质谱方法研究了CF3 I分子多光子电离动力学 ,所用泵浦光及探测光的中心波长分别为 2 6 5和 398nm .获得了母分子离子CF3 I+ 信号及其碎片离子CF3 + 和I+ 信号的寿命衰减常数分别为 (96± 7)、(198± 13)和 (16 7± 6 )fs.这些离子产生的多光子通道机理不同 :CF3 I来自 (1+2′)跃迁 ,单光子泵浦光与CF3 IA带共振 ;驭光子泵浦光激发CF3 I分子到 5 pπ7sδ(2 Π1/ 2 )里德伯态 ,单光子探测光电离产生的母分子离子解离产生CF3 + ;I+ 来自 (2 +2′)和 (1+1′ +2′)The multi-photon dissociative photoionization dynamics of CF3I has been studied with femtosecond two-color pump-probe time of flight mass spectra at a pump pulse of 265 nm and a probe pulse of 398 nm. The life constants of CF3I+ and its fragment ions CF3+ and I+ are obtained as (96 +/- 7), (198 +/- 130) and (167 +/- 6) fs, respectively. The multi-photon dynamics leading to these ions differ. CF3I+ corresponds to a (1 + 2') transition with one-photon pump excitation to the A band of CF3I. CF3+ are mainly formed by a tow-photon probe excitation to the CF3+ with subsequent dissociation of parent ions. I+ are produced in (2 + 2') combined with (1 + 1' + 2') process. The results provide information on the multi-photon pathways involved.

关 键 词：飞秒时间分辨质谱方法 CF3I 光电离 动力学 泵浦-探测 寿命 激发过程 

分 类 号：O657.63[理学—分析化学]