Conformational prediction for molecules containing vicinal lone pairs: Basis set studies for H₂O₂

Abstract

The Dunning and Winter¹ (DW) conformational study of H₂O₂ represents accepted state-of-the-art methodology in accurate SCF computation of molecular properties; nevertheless the prediction of a very short O-O bond length and a very large O-O-H bond angle by DW indicates the difficulty in adequately describing molecules with vicinal lone pairs. Consequently we have reexamined H₂O₂ with several standard Gaussian basis sets, and in addition have investigated the properties of two further basis set prescriptions. While polarization functions are confirmed to be necessary to attaining the correct H₂O₂ conformation, the situation of s (and p) Gaussian bond functions in mid-bond positions is shown to be an economical and efficacious alternative to traditional polarizing functions.