Reactant Coordinate Based State-to-State Reactive Scattering Dynamics Implemented on Graphical Processing Units

A parallel code for state-to-state quantum dynamics with propagation of time-dependent wavepacket in reactant coordinates has been developed on graphical processing units (GPUs). The propagation of wavepacket and the transformation of wavepacket from reactant to product Jacobi coordinates are entirey calculated on GPUs. A new interpolation procedure is introduced for coordinate transformation to decrease the five loop computation to two four loop computations. This procedure has a neglible consumption of extra GPU memory in comparison with that of the wavepacket and produces a considerable acceleration of the computational speed of the transformation. The code is tested to get differential cross sections of H+HD reaction and state-resolved reaction probabilities of O+HD reaction and state resolved reaction probabilities of O+HD for total angular momenta J = 0, 10, 20, and 30. The average speedups are 57.0 and 83.5 for the parallel computations on two c2070 and K20m GPUs relative to serial computation on Intel E5620 CPU, respectively.