An effective nuclear charge model for the prediction of valence force constants in polyatomic molecules. I

The effective nuclear charges have been defined using the quadratic force constants which are obtained by the application of perturbation theory to homonuclear diatomic molecules. It has been shown that these charges are applicable to the calculation of force constants in heteronuclear diatomic molecules. To make further application of the effective nuclear charges to polyatomic molecules, we have proposed effective intramolecular potential functions founded on the electrostatic theorem, and have attempted to predict the force constants of triatomic molecules. The results show that our method of approach using the effective nuclear charges is useful for the prediction of approximate valence force constants in polyatomic molecules.