Calculation of Absolute Raman Intensities of <i>A</i>1 Modes of Molecules and Ions from a Delta-Function Potential Model

Abstract

A delta-function potential model of molecular binding is used to derive an expression for α∥b, the parallel component of the molecular polarizability from the region of a chemical bond, and ∂ᾱ/∂r, the derivative of the mean molecular polarizability with respect to a change in a bond length for the A1 stretching modes of diatomic and polyatomic molecules and ions. The final expression is ∂ᾱ/∂r=23(gσ/Za0)12nr3, in which g is the delta-function strength; Z, the effective nuclear charge; σ, the Pauling covalent bond character; a0, the Bohr radius; n, the number of electrons in the bond region; and r is the equilibrium internuclear distance. There is shown to be good agreement between calculated and experimental values of both α∥b and ∂ᾱ/∂r.