Force-constant computations. Part V. Use of force-constant computations as an aid to frequency assignment in hexachlorocyclotriphosphazene

Abstract

A new procedure is described for the assignment of vibration frequencies with the aid of force-constant calculations. Force-fields are generated for which calculated and observed frequencies agree precisely and the force-fields are examined for consistency with the group-frequency approximation. An ambiguity in the assignment of e′ vibrations in hexachlorocyclotriphosphazene is thereby resolved. The extremal nature of certain force-fields is given a new graphical demonstration. Further improvements in the computational methods for force-constant calculation are described.