Time-dependent wave packet theory for state-to-state differential cross sections of four-atom reactions in full dimensions: application to the HD + OH → H2O + D reaction.

Time-dependent wave packet method has been developed to calculate differential cross section for four-atom reactions in full dimension, utilizing an improved version of reactant-product-decoupling scheme. Differential cross sections for the title reaction were calculated for collision energy up to 0.4 eV. It is found that the differential cross sections for the reaction are all peaked in the backward direction. The majority of H(2)O is produced in the first stretch excited state, with a large fraction of available energy for the reaction going into H(2)O internal motion. As compared in a previous report by Xiao et al. [Science 333, 440 (2011)], the differential cross section at E(c) = 0.3 eV and the differential cross section at the backward direction as a function of collision energy agree with experiment very well, indicating it is possible now to calculate complete dynamical information for some simple four-atom reactions, as have been done for three-atom reactions in the past decades.