Energy and Momentum Conserving Molecular Dynamics

An energy conserving molecular dynamics method has been developed. At each time step, the interacting particles are supposed to exchange quanta carrying energy and momentum. The energy content of a quantum is chosen to match the changes in potential energy, while the momentum transferred is chosen to keep the total momentum of the interacting particles constant. The particles are then moving at a constant speed until the end of next time step. Since the energy is automatically conserved, the time steps may be 10-100 times as great as in conventional MD, which makes the computations faster by at least the corresponding factor. The price to be paid for the improvements is that the actual potential experienced by the particles is partially unknown. Further, there is a small probability for particles to be trapped.