COMPUTATION OF KINETIC CONSTANTS FOR LARGE RANGE INTERNAL MOTIONS IN MOLECULES

This paper presents the development of a software tool for the calculation of the rotational-vibrational G matrix. The program is applied to the study of the kinetic coupling between wagging and methyl torsion in acetone and acetaldehyde. An increase in the coupling is observed when the mass of the wagging atom or the mass of the molecule decreases. This fact becomes very important for the hydrogen wagging in the acetaldehyde molecule. The dependence of kinetic constants on the vibrational coordinates is also analysed. It is found to be small even in the case of large displacements from the equilibrium position