AB-INITIO ADIABATIC AND DIABATIC PERMANENT DIPOLES FOR THE LOW-LYING STATES OF THE LIH MOLECULE - A DIRECT ILLUSTRATION OF THE IONIC CHARACTER

The permanent dipole moments of the eight low-lying (1) Sigma states o f the LiH molecule are calculated by an ab initio approach for both th e adiabatic and the diabatic representations. The results shed light o n the interplay between the ionic and the neutral states producing a d irect illustration of the ionic character of the electronic wavefuncti on. Our results suggest that the location and the width of the avoided crossings for the potential energy curves could be experimentally der ived.