【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 .更多还原

【Abstract】 The spectra from 2000 to 9000 cm -1 which include △v=1～4 (△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 △v=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 SiCl 2 to be a base frame for the stretching vibration of two SiH chromophores, the treatment ignored all the vibrations in the H 2SiCl 2 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 H 2X-type molecule, the Morse dissociation energy D e, the Morse oscillator parameters α and the couple coefficient of the potential energy function f rr′ were determined by fitting the observed vibrational band centers to Hamiltonians matrix. It showed that the H 2SiCl 2 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 1 cm -1. Therefore, the assumption of SiCl 2 being a base frame for the two SiH chromophores is proved to be a good approximation. Substituting the mass of SiCl 2 base frame as the 4th variable into the program, the obtained results indicate that the effective mass of SiCl 2 base frame is 75 .更多还原