Decoupling approximations for quantum vibrational predissociation dynamics: The tests on the low-level golden rule approaches for some rare gas—Cl2, ICl complexes

Vibrational and rotational decoupling approximations are tested in three-dimensional Fermi Golden Rule calculations on energies, lifetimes, and product state distributions of the vibrationally predissociating atom—diatom van der Waals complexes. The validity of approximate separations of diatom vibration, decoupling of stretching and bending intermolecular motions, and rotational infinite order sudden approximation for product scattering is characterized by comparison with the results of accurate calculations on the Ne ··· Cl₂, Ne ··· ICl, and He ··· ICl systems. The most accurate approximate schemes are recommended. © 1996 by John Wiley & Sons, Inc.