Knowledge Bank

In the case of molecules with asymmetric internal rotors, the G-matrix elements and vibrational energy depend explicity upon $\alpha$, the angle of internal rotation. These contributions from the vibrational kinetic energy have been reduced by a perturbation scheme for inclusion in the effective potential hindering the internal rotation. In addition, some contributions of other vibrations to the $\alpha$-dependence of the torsional kinetic energy have been considered.