Study of vib-rotational spectra of van der Waals complexes containing SH4 and CH4

我们利用1998年在我们实验室建立的傅里叶变换微波（FTMW）装置，研究了CD_4-H_20和GeH_4-H_20的转动光谱。最近，我们成功地观测到了CD_4-H_2 O的转动光谱，但没有观测到GeH_4-H_2 O的转动光谱，目前还在寻找中，在寻找CH_4-NO的转动光谱时，观测到了许多反式和顺式HONO和N_2 O_3的吸收线。接下来，我们考虑如何解释已经使用FTMW光谱仪观察到的Ar-SiH 4和Ar-SiD 4的光谱图案之间的差异。这是很难解释观察到的光谱图案只考虑科里奥利相互作用项，耦合的内部旋转的SiH 4和端对端旋转的复杂。然后我们考虑了Ar-SiH_4的货车der Waals伸缩模的各向异性势，并将其展开为货车der Waals键距的幂级数。为了拟合所观察到的Ar-SiH_4和Ar-. SiD 4时，电位阶数分别选择为-15和-9。这些值对应于球形陀螺分子的Lennard-Jones势的排斥力和吸引力。此外，我们还试图用广义内转动Hainiltonian的对角化来解释SiH_4-H_2O体系的转动光谱。SiH_4-H_2O的势垒估计约为260 cm- 1，因为氢键相当强。最后，通过对LiBH_4和NaBH_4振动激发态转动谱的分析，确定了它们的能量差和Coriolis相互作用常数。

We have searched for rotational spectra of CD4--H20 and GeH4--H20 using a Fourier transform microwave (FTMW) machine which was built in our lab in 1998. Very recently we succeeded in observing the rotational spectra of CD4--H20, However, we could not detect a spectrum of GeH4--H20 and are still searching it. When a rotational spectrum of CH4--NO was searched, many absorption lines of trans- and cis-HONO and N2O3 were observed. Next we considered how to explain the difference between the spectral patterns of Ar--SiH4 and Ar--SiD4 which had already been observed using a FTMW spectrometer. It was difficult to explain the observed spectral patterns considering only a Coriolis interaction term, which couples the internal rotation of SiH4 and the end-over-end rotation of the complex. Then we considered an anisotropic potential of a van der Waals stretching mode for Ar--SiH4 and expanded this potential by a power series of van der Waals bond distance. In order to fit the observed spectral patterns of Ar--SiH4 and Ar-. SiD4, the potential orders were chosen to be -15 and -9, respectively. These values were corresponded to the repulsive and attractive forces of the Lennard-Jones potential for a spherical top molecule. In the addition, we tried to explain the observed rotational spectra of SiH4--H20 system by taking account for a diagonalization of the general internal rotation Hainiltonian. The potential barrier of SiH4--H20 was estimated to be about 260 cm- 1 because of rather strong hydrogen bonding. Finally, analyzing the rotational spectra of the excited vibrational states for LiBH4 and NaBH4, the energy differences and the Coriolis interaction constants were determined.