Improved Vibrational Potential for Diatomic Molecules

Abstract

Previous methods used to obtain approximate vibrational potentials for diatomic molecules have led to potentials which are unsatisfactory at large internuclear separations. This paper presents a method by means of which more satisfactory potentials can be constructed. Poeschl-Teller functions are fitted to data near equilibrium, and to these functions are added perturbations of the form T·tanh2avα(r—r0). The perturbations adjust the approximate potentials at large internuclear separations. This method is applied to several electronic states of H2, D2, and T2. The resulting functions are good approximations to the true potentials even for relatively large internuclear separations. Very near dissociation the approximate potentials deviate from the true potentials in a consistent manner.