Electrooptical parameters and polar tensors of some XY 3 type molecules

Abstract

The electrooptical parameters of some XY 3 (X = P, N; Y = F, H) pyramidal type molecules are calculated using the transformation matrix obtained by the virial theorem approach. The sign combinations of the various modes of vibration have been predicted by calculating the equilibrium dipole moment of the molecules. The results using this method are at variance with those of other methods of choosing the correct signs of the dipole derivatives. Polar tensors for the constituent atoms of the molecules for the preferred sign combination are determined and the intensity sum rule verified.