The large-amplitude motions in quasi-symmetric top molecules with internal C3 v rotors : Interpretation of the low frequency Raman spectrum of disiloxane

Abstract

The vibration-torsion-rotation Hamiltonian developed previously has been used to study the skeletal bending-torsion-rotation energy levels of disiloxane. The zeroth-order skeletal bending-torsion-rotation Hamiltonian for a molecule of this type is presented. The symmetry classification of the molecular wavefunctions and energy levels as well as infrared and Raman selection rules are considered. The energies of the skeletal bending-torsional-rotational states have been calculated and these results are used to interpret the low frequency Raman spectra of gaseous disiloxane- d 0 and disiloxane- d 6. It is shown that the treatment presented enables one to properly interpret these spectra. The results are compared to those obtained with other more approximate Hamiltonians.