Diatomics-in-molecules models for H2O and H2O−. II. A self-consistent description of the 1A′, 1A″, 3A′, and 3A″ states of H2O

Abstract

This paper describes a small (6 to 9 basis functions) model for the potential energy surfaces relevant to the chemical reaction O(1 D)+H2→OH(X 2Π)+H. The model is optimized with respect to the 1 A ′ and 1 A ″ states correlating with the reagents and products of this reaction; this is done in such a way as to simultaneously provide a qualitatively correct description of the 3 A ′ and 3 A ″ states of H2O. In this sense the model is self‐consistent. In agreement with other semiempirical work, the results indicate that two 1 A ′surfaces and one 1 A ″surface are pertinent for a dynamical study of this reaction. The model adequately represents the most important features of H2O potential energy surfaces and is at the same time small enough to be used d i r e c t l y in a trajectory calculation of the reaction cross section.