The action of transformations of the point group of a molecule on its instantaneous nuclear configuration

The action of the transformations of a point group of a rigid molecule in a specified electronic state on the instantaneous nuclear configuration of the molecule is considered. This action is shown to be equivalent to permutations of identical nuclei in the effective potential of interaction of the nuclei in this state, which is invariant with respect to the transformations of the point group. Therefore, the point group characterizing the electronic state should be used as the rigorous symmetry group of the total electronic-vibrational-rotational motion.