The application of an effective nuclear charge model to the prediction of valence force constants in trigonal bipyramidal XY 5 molecules—IV

Abstract

An effective nuclear charge model previously proposed is applied to the calculation of valence force constants for trigonal bipyramidal XY 5 molecules. Some new expressions relating the valence force constants to the effective nuclear charges are derived for such molecules. From these expressions, the various types of force constants for seven molecules are calculated with the use of the effective nuclear charges and the geometric parameters and compared with the experimental force constants which are determined by the normal coordinate analysis. The results show that the effective nuclear charge model is useful for semiquantitatively predicting the valence force constants for more complicated polyatomic molecules as well as XY 5 type molecules.