Binding Energy and Dipole Moment of Alkali Halide Molecules

Abstract

A simple theory of alkali halide gas molecules in the spirit of Born-Mayer lattice theory is presented. The molecule is considered to be constituted of ions, each of which is polarized by the electrostatic field of the other. This deformation polarization has two important consequences: (1) the net dipole moment of the molecule becomes appreciably lower than that given by the product of the electric charge e, and the internuclear separation a; (2) the repulsion constants (determined from empirical data) become different from the corresponding constants for the crystal. The theory yields satisfactory results for the binding energy, vibration frequency, and dipole moment, μ, in all instances where necessary data are available. In cases where the internuclear distances are not known experimentally, they are calculated from the theory using experimental binding energies. It is possible to assign to the ions Goldschmidt-like radii, the sums of which reproduce reasonably well both the calculated and the observed internuclear distances. Finally, item (1) above explains why Pauling's criterion for the fraction of ionic character, f=μ/ea, is not a very good measure of ionicity for these completely ionic substances.

A New Relation between Dissociation Energy and Molecular Constants of Diatomic Molecules

“…Somayajulu calculated 7 the dissociation energy of diatomic molecules using the relation (kere) /D0 = S, where ke is the force constant for infinitesimal amplitude, re the internuclear equilibrium distance, D0 the dissociation energy, and S a constant for a sequence. The results obtained with this relation did not agree with those estimated by Rittner 8 , Katti et al 9 and Varshni 3 . Recently, a relation connecting the dissociation energy with the molecular constants of diatomic molecules in the Sutherland potential function 10 , has been given by Tandon and Tandon n .…”

TRAJECTORY SIMULATION OF RECOMBINATION MECHANISMS IN SYSTEM Cs+ + Br- + Xe

“…Для описания межионного взаимодействия в молекулах галогенидов щелочных металлов наиболее часто используется так называемый усеченный потенциал Риттнера [35,36], имеющий вид:…”

Luminescence and formation of alkali-halide ionic excimers in solid Ne and Ar

“…1 are based on the truncated Rittner potential (at 1/r 4 ) with the effect of the dielectric host taken into account by introducing the 1/e factor into the coulombic and 1/r 4 terms. Bond lengths and polarizabilities are taken from literature [4,14]. For the lower A + X state the Born-Mayer potential…”