The electronic structure of the calcium monohalides. A ligand field approach

The electronic structure of the calcium monohalides is addressed using a ligand field model which approximates the halide as a polarizable negative charge perturbing the one electron valence structure of the Ca+ ion. A simple, zero-free-parameter model is shown to predict accurately electronic energies, transition moments, permanent dipole moments, and several other molecular constants that have been experimentally determined. The molecular properties and electronic wave functions are interpreted in terms of the polarization (s/p/d/f mixing) and radial expansion (nl/n+1l mixing) of the low lying, free ion, basis functions caused by the electric field of the ligand.