Coupled equations applied to the photodissociation of linear triatomics: A test of approximate schemes for calculating the line shape and the effect of final states interactions

Abstract

Coupled equations are used to obtain the line shape and the final probability distribution of linear triatomic molecules undergoing photodissociation. These calculatins provide a test for some current approximations made in the evaluation of the one‐dimensional nuclear overlap integrals needed for the bound‐free couplings. The linearization of the repulsive potential yiels a line shape of correct position and width, although with a somewhate reduced area. The uniform Airy approximation is superior at most energies but may fail at some energy within the line shape. This behavior can be related to a small difference in slopes of the potentials at a crossing point. A study has also been made of the half‐collision formalism which relates the probability distribution for the vibrational states of the diatomic fragment to bound–free couplings and matrix elements of the transition operator on the repulsive surface. It is found that this procedure underestimates the rearrangement of probabilities resulting from final states interactions.