Large-scale efficient Langevin dynamics, and why it works

An effective method with large convergence tolerance for self-consistent-field calculations is proposed to accelerate Born-Oppenheimer molecular-dynamics simulations based on the density functional theory. The errors for forces with large convergence tolerance are taken as the noises of Langevin dynamics for constant-temperature molecular dynamics. We use different systems such as crystalline Si, liquid Si and liquid water to verify the accuracy and efficiency of the method. Results of the new method are consistent with those of sufficiently accurate methods and the dynamical properties of the systems are reproduced as well. The efficiency of computation is improved by a factor of two to three using this model. Our analysis provides three reasons which explain why the method works. This development effectively extends the application of Born-Oppenheimer molecular dynamics to larger systems. Copyright (c) EPLA, 2009