On simplifying the potential for alkali halide molecules

Abstract

Two new analytical forms for the interaction potential of alkali halide molecules have been proposed. It is shown that these forms for the potential generate from a knowledge of the effective electron density function F( r) which enters the Poisson equation ∇ 2 U= F( r). In each of these a new constant assumed to be characteristic of the molecules has been introduced. The constants simply correlate with effective charge and effective distance parameters and also with the principal quantum numbers (or with the effective principal quantum numbers as in model I) of the valence electrons of the combined ions that are independent of experimental data. Various spectroscopic constants, namely the ionic dissociation energy D i, the vibrational rotational coupling constant α e, and vibrational anharmonicity constant ω e x e, have been calculated for these and for the Varshni and Hellmann potential functions. Comparisons of these constants show the proposed models to be much better than the older ones.