Infrared spectra of HF complexes with methane, silane, and germane

Abstract
HF complexes with methane, silane, and germane were prepared in noble gas matrices and studied using infrared spectroscopy and Hartree–Fock (SCF) calculations. The spectra indicate that two types of 1:1 complexes were formed, a normal one in which the hydrogen of HF is interacting with one hydrogen of silane or germane, and a reverse complex in which the fluorine of HF is interacting with one hydrogen atom of methane. The IR inactive symmetric C–H stretch in CH4 was observed in the CH4‐‐FH complex as a weak band at 2914 cm1. In the silane‐‐HF and germane‐‐HF complexes, the Si–H and Ge–H stretches were perturbed approximately 50 cm1 to higher energy relative to the antisymmetric stretch ν3 in each parent molecule, but the ν1 modes were masked by the strong ν3 parent bands. Higher order 1:2 (AH4:HF) complexes were also observed and support the normal or reverse‐type geometry of the 1:1 complexes.