3-DIMENSIONAL QUANTUM WAVE-PACKET STUDY OF THE AR-HCL PHOTODISSOCIATION - A COMPARISON BETWEEN TIME-DEPENDENT SELF-CONSISTENT-FIELD AND EXACT TREATMENTS

The time-dependent self-consistent-field (TDSCF) approximation is used to study the photodissociation of the Ar-HCl cluster in a three-dimen sional framework. The results are compared with numerically exact quan tum calculations, and the properties and accuracy of the TDSCF approac h are evaluated on this basis. The TDSCF approximation is used in Jaco bi coordinates, and the total wave function is factorized into a wave packet for two coordinates associated with the H atom, and a wave pack et for a single coordinate that describes the relative motion of the h eavy particles. Quantitative agreement between the TDSCF and the exact results is found for most quantities calculated. The calculations sho w that photodissociation, and in particular the departure of the H ato m is predominantly a direct process, but an appreciable amount of wave packet amplitude moving in excited state resonances is also found. Th is amplitude seems significantly larger than obtained in recent calcul ations by Schroder et al. [J. Chem. Phys. 100, 7239 (1994); Chem. Phys . Lett. 235, 316 (1995)]. The validity and computational efficiency of the TDSCF approach for realistic systems of this type is discussed. ( C) 1995 American Institute of Physics.