Predissociation in diatomic spectra with special reference to the Schumann-Runge bands of O₂

Abstract

It is shown how the predissociation probabilities for the vibrational levels of a bound state of a diatomic molecule, crossed by a repulsive state may be calculated, knowing accurate potential energy curves for both. The expected maximum occurs for vibrational levels near the crossing point but several subsidiary maxima may occur above this. It has been found that the results are very sensitive to the form of the repulsive curve. For the Schumann-Runge absorption band of O₂ we find the observed predissociation can be explained by a single crossing near v' = 4 by a repulsive curve having the form: