Molecular Dynamics Simulations: The Limits and Beyond

This article reviews the present state of Molecular Dynamics (MD) simulations and tries to give an outlook into future developments. First an overview is given of methods, algorithms and force fields. After considering the limitations of the standard present-day techniques, developments that reach beyond the present limitations are considered. These concern three major directions: (a) inclusion of quantum dynamics, (b) reduction of complexity by reducing the number of degrees of freedom and averaging over interactions with less important degrees of freedom, (c) reduction to mesoscopic dynamics by considering particle densities rather than positions. It is concluded that MD is a mature technique for classical simulations of all-atom systems in the nanosecond time range, but is still in its infancy in reaching reliably into longer time scales.