Calculated octic centrifugal distortion coefficients of non-linear molecules

Abstract

The equilibrium octic centrifugal distortion coefficients of a molecule are coefficients of terms of the type H ˜ 08 in the expansion of the effective Hamiltonian. They depend on the quartic potential constants k k l m n ′ for the vibrational modes that have non-zero inertial derivatives, and therefore give information on these constants additional to that given by the other terms that depend on the quartic potential, H ˜ 24 and H ˜ 40 . The present work describes the calculation of these H ˜ 08 terms from a given potential by perturbation theory, using a computer program that calculates the coefficients in the successive contact transformations. Results are presented for the SO 2, ClO 2, O 3, and H 2O molecules.