Wave packet dynamics of van der Waals molecules: Fragmentation of NeCl2 with three degrees of freedom

We study the time evolution of wave packets describing the fragmentation of NeCl2 complexes with three degrees of freedom (total angular momentum J=0). The method of calculation involves a combination of the Fourier method to treat the dissociative degree of freedom (van der Waals stretching coordinate) and a basis set of expansion to treat the intramolecular degrees of freedom (vibration and rotation of the diatomic fragment). Resonance energies, lifetimes, and product distributions can be extracted from the evolving wave packets. Results are presented for van der Waals complexes prepared initially with zero-point energy in the van der Waals modes and several different Cl2 vibrational excitations. Two different model potential energy surfaces are considered. The fragmentation mechanism is further explored by inspection and analysis of the wave function at various time intervals.