Overtone spectrum and the Fermi resonance of the SiH chromophore in SiHCl3

The Fourier transform and Fourier transform intracavity laser absorption sp ectra of the gas phase SiHCl3 molecule were recorded from 1000 cm(-1) up to 13 000 cm(-1). The normal mode analysis is carried out to rt the observed band centres. The reduced Hamiltonian models in terms of normal and curvili near internal coordinates are used to study the Fermi resonance between the SiH stretching and bending modes and analyse the observed band centres ass ociated with the SiH chromophore. The resonance in the SiH chromophore is f ound not to be important due to the cancellation of the contributions from the kinetic and the potential coupling terms. Off-diagonal anharmonic const ants between the SiH stretching and bending manifold and the molecular fram e have been determined. The SiH chromophore vibrational intensities are als o reported.