A b i n i t i o calculation of the X 1Σ+ and A 1Σ+ states of CsH

Abstract
The structure of the X 1Σ+ and A 1Σ+ states of the CsH molecule has been calculated by a modified effective core potential (ECP) method. An extensive Gaussian basis set was required to accurately describe the diffuse electron charge distribution. The computed potential energies agree well with experimental results for internuclear separations larger than 6a0, where the ECP method is valid. The electric dipole and transition moments have also been calculated; they are presented here and compared with experiment by Yang et al., to be published in a subsequent paper.