A general method of obtaining wavefunctions for empirical diatomic molecular potential functions has been given. Efficacy of the method has been tested by computing Franck-Condon factors for some bands of a new system of SiO using Morse oscillator model and these have been compared with the ones obtained using exact Morse wavefunctions. It is concluded that the method is satisfactory at low quantum numbers.

Hulbert-Hirschfelder (h-h) potential function has been used to obtain the relative vibrational transition probabilities for the observed bands of the first positive system of nitrogen molecule. The vibrational wavefunctions have been calculated by solving the Schrödinger equation by the method due to Langer, at low vibrational quanta and by thewkb method at high vibrational quanta. It is established that theh-h potential is superior to the often used Morse potential function for the transition under consideration.