Time-Dependent Wave Packet Dynamics Calculations of Cross Sections for Ultracold Four-Atom Reactions.

We report here the first time-dependent wave packet dynamics study for an ultracold four-atom reaction. Our calculations provide accurate integral cross sections and rate constants all the way down to the Bethe-Wigner threshold regime for the benchmark OH + H2(v = 2, j = 0) → H2O + H reaction, indicating that the time-dependent wave packet method is a powerful tool for studying ultracold four-atom reactions.