Ab initio interactive molecular dynamics on graphical processing units (GPUs).

A virtual molecular modeling kit is developed based on GPU-enabled interactive ab initio molecular dynamics (MD). The code uses the TeraChem and VMD programs with a modified IMD interface. Optimization of the GPU accelerated TeraChem program specifically for small molecular systems is discussed, and a robust multiple time step integrator is employed to accurately integrate strong user-supplied pulling forces. Smooth and responsive visualization techniques are developed to allow interactive manipulation at minimum simulation rates below five MD steps per second. Representative calculations at the Hartree-Fock level of theory are demonstrated for molecular systems containing up to a few dozen atoms.