Determination of proper time step for molecular dynamics simulation

Abstract

In this study we have investigated the determination of proper time step in molecular dynamics simulation. Since the molecular dynamics is mathematically related to nonlinear dynamics, the analysis of eigenvalues is used to explain the relationship between the time step and dynamics. The tracings of H-2 and CO2 molecular dynamics simulation agrees very well with the analytical solutions. For H-2, the time step less than 1.823 fs provides stable dynamics. For CO2, 3.808 fs might be the maximum time step for proper molecular dynamics. Although this results were derived for most simple cases of hydrogen and carbon dioxide, we could quantitatively explain why improperly large time step destroyed the molecular dynamics. From this study we could set the guide line of the proper time step for stable dynamics simulation in molecular modeling software.