Lower vibrational states of SO 2. Density functional and discrete variable representation approach

Abstract

A set of lower vibrational levels of SO 2 ( 1A 1) has been calculated with inclusion of anharmonic effects. The discrete variable representation of bending coordinate and a two-dimensional distributed Gaussian basis expansion for stretching coordinates have been used. Complete quartic force fields in three dimensions have been constructed, based on density functional theory (BLYP, B3LYP, B3PW91) and CASSCF(14/10) calculations. Our results indicate the B3LYP approach as the best one for reproduction of the observed vibrational excitation energies and a set of Dunham-type spectroscopic constants for the molecule studied.