390.60nm激光作用下Si(CH_3)_4的多光子解离与硅原子的(1+1)电离  

Multiphoton dissociation of Si(CH_3)_4 and (1+1)ionization of Si at 390.60nm laser radiation

作　　者：施德恒[1] 刘新建[2] 刘玉芳[3] 

机构地区：[1]空军第一航空学院基础部 [2]信阳师范学院 [3]河南师范大学物理系,河南新乡453002

出　　处：《激光杂志》2002年第5期39-41,共3页Laser Journal

摘　　要：在390.60nm的紫外激光作用下,利用超声分子束技术与飞行时间（TOF）质谱仪相结合的方法研究了气相四甲基硅分子多光子电离（MPI）的TOF质谱,在较低能量的激光作用下主要检测到了Si（CH3）+、Si+、C2+等离子的信号,有时甚至只检测到了Si+离子的信号;在较高能量的激光作用下主要检测到了Si（CH3）+H（n=1,2,3,4）、Si+、C2+甚至还有SiC3+,SiC2+等离子的信号。据此并结合以前得到的结论,讨论了四甲基硅分子可能的MPI过程。得出了Si+主要来自于Si（CH3）4的多光子解离-Si原子的（1+1）电离,Si（CH3）+H（n-1,2,3）主要来自于Si（CH3）H（n=1,2,3）的（3+1）电离、Si（CH3）+4来自于Si（CH3）4的（3+1）电离的结论。The time-of-flight (TOF) mass spectra distribution of the multiphoton dissociation/ ionization of tetramethylsilane in a supersonic molecular beam was investigated with a TOF mass spectrometer at 390.6nm laser radiation. In our experiments, TOF mass spectra showed that Si(CH3)+. Si+ C2+ sometimes only Si+, C2+ appeared at lower energy laser radiation but Si(CH3)+ (n=l, 2, 3, 4) , Si+, C2+, even SiC3+, SiO2constantly appeared at higher laser radiation. According to these experimental results, the possible MPI channels of this molecule were discussed. The conclusion was gained that Si+ions might be mainly produced via a sequential photo-dissociation to form Si atoms first and followed by a (1+1) ionization of Si atoms. Si(CH)+n (n=1,2,3)ions might be mainly produced from self-ionization of neutral fragments Si(CH3)n(n=l, 2,3),and the Si+(CH3)4+ions might be produced from (3+1) ioniza.tion of parent molecule.

关 键 词：390.60nm激光 四甲基硅 飞行时间质谱 反应动力学 多光子解离电离 多光子电离解离 硅原子 

分 类 号：O436[机械工程—光学工程]