Three-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-dimensional framework. The results are compared with numerically exact quantum calculations, and the properties and accuracy of the TDSCF approach are evaluated on this basis. The TDSCF approximation is used in Jacobi coordinates, and the total wave function is factorized into a wave packet for two coordinates associated with the H atom, and a wave packet for a single coordinate that describes the relative motion of the heavy particles. Quantitative agreement between the TDSCF and the exact results is found for most quantities calculated. The calculations show that photodissociation, and in particular the departure of the H atom is predominantly a direct process, but an appreciable amount of wave packet amplitude moving in excited state resonances is also found. This amplitude seems significantly larger than obtained in recent calculations by Schröder 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.