PNNL

Abstract

We report a highly correlated multi-reference configuration interaction calculation of the near-equilibrium potential energy surface of ozone using a large correlation consistent basis set. Three-dimensional analytical expressions are obtained for the potential energy and dipole moment functions using least-squares fits to ab initio points near the equilibrium geometry. Low-lying vibrational band origins of 16O3 and some of its isotopic variants are calculated using the ab initio potential energy function. The calculated fundamental frequencies for the symmetric stretching and bending vibrations are within about 3 cm-1 of the observed values, while that for the anti-symmetric stretch deviates from experiment by about 13 cm-1. The agreement with experiment can be significantly improved if the ab initio potential energy function is scaled in the anti-symmetric stretching coordinate. Absolute infrared absorption intensities are also calculated using ab initio electric dipole moment functions and are in good agreement with the available experimental data.