Correlations of bending mode force constants among polyatomic molecules

Abstract

A Coulombic interaction potential is used to describe the bending mode force constant, fφ, of triatomic and larger molecules. It gives the relation fφ/r1r2 = cz1z2R-5[3r1r2 sin2 φ - R2 cos φ], z1 and z2 being the charges of the two bonds involved, φ the bond angle, r1 and r2 the bond lengths, R the distance between the two end atoms, and c a proportionality constant. For many different types of molecules, the product cz1z2 is shown to be nearly constant among molecules of each type. The above relation thus allows a ready estimation of fφ for a molecule from data available for molecules of the same type. © 1983 American Chemical Society.