On the use of variational wavefunctions in calculating vibrational band intensities

Abstract

It is shown that vibrational band intensities calculated using variational wavefunctions and dipole surfaces give results which depend on how the Cartesian axes of the dipole surface are defined. It is suggested that the most consistent definition of these axes uses the rules proposed by Eckart for separating rovibrational motion. The consequences of this choice of axis system for the calculated band intensities of H2S, LiNC and H3 +, and the apparent validity of Hönl-London factors are discussed. Computed band intensities are presented for H2S, HDS and D2S which correct previous literature values.