A full-dimensional quantum approach to the vibrational predissociation of tetra-atomic complexes based on the partially-separable time-dependent self-consistent-field approximation

摘要

A full-dimensional time-dependent quantum approach is proposed to study the vibrational predissociation (VP) dynamics of BC-Rg_2(BC=diatomic molecule,Rg=rare-gas atom)cluster.The method applies the partially-separable time-dependent self-consistent-field approximation to express the six-dimensional total wave function as a product of two wave functions, one describing the three stretching modes of the system,the other one describing the three bending modes.The method is tested by simulating the VP of Cl_2-Ne_2 for the initial Cl_2 vibrational excitations v-7-13,and of I_2(v=21)-Ne_2.THe Cl_2-Ne_2 results are compared to experimental data and earlier simulations.The method is very efficient as compared to previous reduced-dimensional quantum models where the bending modes were not explicitly considered in the dynamics.Good agreement with experiment is found for the resonance lifetimes and Cl_2 vibrational distribut6ions for V>=9,where the bending/stretching couplings are not strong.The model underestimates rotational excitation of the CL_2 fragment,failing to reproduce the Cl_2 retational distributions.In the case of I_2 (v=21)-Ne_2,the time evolution of the vibrational populations is compared with previous multiconfiguration time-dependent Hartree calculations.The favorable comparison obtained supports the reliability of the method within certain validity conditions.