A new, practical method of computing mean amplitudes of vibration and perpendicular amplitude correction coefficients

Abstract

A new approach for calculating mean amplitudes of vibration ( u), perpendicular amplitude correction coefficients ( K) - used in the calculation of R α structures and shrinkage effects - and related quantities are presented. The method is based on an expansion of interatomic distances in terms of the cartesian displacement coordinates. This leads to a practical way of calculating the u and K values, which is convenient for computer solution. Only a short subroutine is necessary in addition to a normal coordinate program by W.D. Gwinn in order to perform these calculations.