I am interested in theoretical calculations and simulations of the kinetics and dynamics of molecules and radicals in the gas phase. What dynamical processes control reactive and inelastic encounters between molecules and radicals? How do these processes change with pressure and temperature? How do uncertainties in potential energy surfaces influence our calculated kinetics and dynamics? How can we exploit computer parallelism to accelerate the quantity and quality of our calculations? In collaboration with others in the group, we attempt to answer these questions with a range of classical to quantum methods using laptops to massively parallel computers. In particular, we are investigating molecular dynamics in bath gases at high pressures, bimolecular reactive tunneling with semi-classical methods, anharmonic partition functions with semi-classical techniques, uncertainty propagation in gas-phase combustion reactions, and highly parallelized localized-orbital electronic structure methods for large systems.