A test of the rotational infinite order sudden approximation in molecular fragmentation

Abstract

A quantum mechanical close-coupling calculation is presented for predissociation of a triatomic molecule and the results are compared with the infinite order sudden approximation for rotational motion (RIOSA). The calculations are performed for a model system which mimics the predissociation of the zero-point level of N2O+(Ã). It is shown that for the case treated here the infinite order sudden approximation obtained by setting all the rotational energies equal to zero gives poor results. Good agreement between RIOSA and exact calculations is obtained by setting them equal to the average rotational energy in the fragments. The relationship between RIOSA as applied to full collisions and half-collisions is also discussed.