QUANTUM-MECHANICAL 3-DIMENSIONAL WAVEPACKET STUDY OF THE LI-]LIF+H REACTION(HF)

A three-dimensional time-dependent quantum mechanical wavepacket metho d is used to calculate the state-to-state reaction probabilities at ze ro total angular momentum for the Li + HF --> LiF + H reaction. Reacti on probabilities starting from several different initial HF vibrationa l-rotational states (v=0,j=0,1,2) and going to all possible open chann els are computed over a wide range of energies. A single computation o f the wavepacket dynamics yields reaction probabilities from a specifi c initial quantum state of the reactants to all possible final states over a wide range of energies. The energy dependence of the reaction p robabilities shows a broad background structure on which resonances of varying widths are superimposed. Sharp resonance features seem to dom inate particularly at low product translational energies. There are ma rked changes in the energy dependence of the reaction probabilities fo r different initial or final diatom rotational quantum numbers, but it is noticeable that, for both reactants and products, odd and even rot ational quantum numbers give rise to similar features. Our results cle arly identify some resonance features which are present in the reactio n probability plots for all product and initial states, though they ap pear in the form of sharp peaks in some plots and sharp dips in others . We speculate that these features arise from reactive scattering reso nances which serve to redistribute the flux preferentially to particul ar product quantum states. The present calculations extend to higher e nergies than previously published time-independent reactive scattering calculations for this system. (C) 1996 American Institute of Physics.