POPULATION ANALYSIS FROM ATOMIC POLAR TENSORS

Atomic charges derived from atomic polar tensors are calculated by the ab initio method using a 6-31G** basis set. This charge, Q(alpha) as defined, is invariant under rotation of the coordinate system, and their sum for all atoms in the molecule is zero. A test with water and ammonia molecules shows that it is almost invariant with respect to the basis set. A linear relationship is found between the atomic charge, Q(alpha), and the partical charge for the hydrogen atom which is calculated using the equalization of the electronegativity principle. Also, an excellent linear regression is obtained when Q(alpha) is ploted against the IR experimental charge.