Sudden approximation for collision-induced dissociation

Collision-induced dissociation (CID) in atom - diatom non-reactive systems is studied quantum mechanically by treating the rotational and vibrational degrees of freedom in a sudden approximation. The collision problem to be solved is reduced to a one-dimensional Schrödinger equation with respect to the intermolecular radial distance. Therefore, only the scattering phase shift is an important quantity, and a physical insight into the collision dynamics can be obtained by observing the dependence of the scattering phase shift on the molecular orientation and on the internuclear distance of the molecule. The sudden approximation is applied to collisions. The present result indicates the applicability of the sudden approximation to CID in general cases of heavier diatomic or polyatomic molecules.