THE VIRIAL THEOREM AND INTERNAL $ROTATIONS^{*}$

Abstract

“The virial theorem is used to show that the barrier to internal rotation. $\Delta $W, is \[ \Delta W={^{1}/_{2}}\Delta <V>=-\Delta<T> \] where V is the total electrostatic potential energy operator, T is the electronic kinetic energy operator and the average is over electronic space. These criteria, which are exact within the Born-Oppenheimer approximation, are applied to some of the theoretical models that have previously been proposed for internal rotations.”