Theory of interionic forces in alkali halide molecules

A modified treatment of the interionic forces for alkali halide molecules is presented within the framework of Rittner’s model. The electronic polarizabilities of ions in the molecular state are calculated using an energy level analysis. The free ion polarizabilities used in Rittner’s model are replaced by the molecular state polarizabilities. The contributions arising from the van der Waals interactions and the mutual polarization of ions are recalculated. Values of the dipole moment, the binding energy, and the rotational and vibrational constants are estimated for twenty alkali halides using two alternative potential forms for the repulsion energy. The results are discussed in the light of experimental data.