410～355nm内四甲基硅的多光子解离和电离研究  

Multiphoton dissociation and ionization study of tetramethylsilane at 410～355 nm laser radiation

作　　者：施德恒[1] 刘玉芳[2] 

机构地区：[1]空军第一航空学院基础部,信阳464000 [2]河南师范大学物理系,新乡453002

出　　处：《原子与分子物理学报》2002年第2期126-132,共7页Journal of Atomic and Molecular Physics

摘　　要：利用平行板电极装置研究了四甲基硅在 410～ 378nm内的MPI光谱 ;利用TOF质谱仪研究了该分子在 40 2～ 371nm内若干个波长点处的TOF质谱 ;利用四极质谱装置研究了它在 35 5nm处的MPI质谱。测得了 35 5nm下Si(CH3 ) + n(n =1,2 ,3,4)及Si+ 的激光光强指数 ,以及其信号强度占总信号强度的分支比随光强的变化关系。据此 ,讨论了该分子MPI过程的可能通道 ,得出了Si+ 主要来自于母体分子的多光子解离 硅原子的电离、Si(CH3 ) + n(n =1,2 ,3)主要来自于Si(CH3 ) n(n =1,2 ,3)的自电离、Si(CH3 ) + 4来自于母体分子的(3+1)电离的结论。This paper studies the multiphoton ionization (MPI) spectra of tetramethylsilane with a parallel plate vacuum cell by laser of 410～378 nm and its time-of-flight (TOF) mass spectra using a TOF mass spectrometer by laser of 402～371 nm, and investigates MPI mass spectra of this molecule at 355 nm laser radiation by means of a quadrupole mass spectrometer. The dependence of the signal intensity of the ions Si(CH 3) + n(n=1,2,3,4) Si + on laser power is measured. The fractions of signal Si(CH 3) + n(n=1,2,3,4) and Si + vs. Laser intensity are obtained. According to these, the possible MPI channels of this molecule are discussed. The conclusion is gained that Si + ions might be mainly produced via a sequential photo-dissociation to form Si atoms first and followed by a multiphoton ionization of Si atoms, Si(CH 3) + n(n=1,2,3) ions might be mainly produced from self-ionization of netral fragments Si(CH 3) + n(n=1,2,3), and the Si(CH 3) + 4 ions might be produced from (3+1) ionization of parent molecule.

关 键 词：甲四基硅 多光子解离 多光子电离 反应动力学 质谱 分子物理 

分 类 号：O561.4[理学—原子与分子物理]