H_2SiCl_2分子Si-H振动“基座”SiCl_2的有效质量  

The Effective Mass of Base Frame SiCl_2 for Si-H Chromophores Stretching Vibrations in H_2SiCl_2

作　　者：陈平[1] 郑晶晶[1] 刘安雯[1] 何圣贵[1] 胡水明[1] 郝绿原[1] 

机构地区：[1]中国科学技术大学,中国科学院选键化学重点实验室,合肥230026

出　　处：《Chinese Journal of Chemical Physics》2003年第3期166-170,共5页化学物理学报（英文）

基　　金：国家自然科学基金资助项目 ( 10 2 740 77;2 0 10 3 0 0 7;2 970 3 0 0 7)

摘　　要：用傅立叶变换光谱仪和激光腔内吸收光谱仪记录了H2 SiCl2 分子 2 0 0 0～ 90 0 0和 12 0 0 0～ 12 90 0cm-1的红外吸收光谱 .依据局域模理论的非谐性耦合非谐振子 (ACAO)模型 ,分析并拟合了Si-H的对称伸缩振动和反对称伸缩振动 ,得到描述Si-H伸缩振动的Morse离解能De、Morse振子参数α和键振子势能耦合系数frr′.分析中忽略了SiCl2 “基座”对Si-H伸缩振动的影响 ,拟合结果与实验值符合的很好 ,拟合方差小于 1cm-1,表明这一近似是可取的 .分析拟合结果表明 ,Si-H振动时“基座”SiCl2 的有效质量为 75 .The spectra from 2000 to 9000 cm(-1) which include Deltanu = I similar to 4 ( A v = m + n; m and n are vibrational quanta of excitation in two bonds) band of SiH stretching vibration were recorded by a Bruker IFS 120HR Fourier transform spectrometer. The Fourier transform intracavity laser absorption spectroscopy (FT-LCLAS) was used to record the band of Deltanu = 6 SiH stretching vibration around 12345 cm(-1). The Blackman-Harris-3-Term was adopted the apodization function in FTIR. The resolution of all the obtained spectra is 0.2 cm(-1). The Si - H symmetric and asymmetric stretching vibrational modes were assigned. Assuming the SiCl2 to be a base frame for the stretching vibration of two SiH chromophores, the treatment ignored all the vibrations in the H2SiCl2 molecule except the two SiH stretching vibrations. Adopting the anharmonically coupled anharmonic oscillator local mode model ( ACAO) and using the program used to optimize the spectroscopic constants of the H2X-type molecule, the Morse dissociation energy D-e, the Morse oscillator parameters alpha and the couple coefficient of the potential energy function f(n), were determined by fitting the observed vibrational band centers to Hamiltonians matrix. It showed that the H2SiCl2 molecule has stronger anharmoic character and weaker inter-bond coupling. The fitting results are in good agreement with the observed levels and the standard deviation of fitting is less than I cm(-1). Therefore, the assumption of SiCl2 being a base frame for the two SiH chromophores is proved to be a good approximation. Substituting the mass of SiCl2 base frame as the 4th variable into the program, the obtained results indicate that the effective mass of SiCl2 base frame is 75.

关 键 词：局域模 伸缩振动 有效质量 基座 

分 类 号：O641.1[理学—物理化学] O657.3[理学—化学]