title: Constant pressure and temperature discrete-time Langevin molecular dynamics.
abstract: We present a new and improved method for simultaneous control of temperature and pressure in molecular dynamics simulations with periodic boundary conditions. The thermostat-barostat equations are built on our previously developed stochastic thermostat, which has been shown to provide correct statistical configurational sampling for any time step that yields stable trajectories. Here, we extend the method and develop a set of discrete-time equations of motion for both particle dynamics and system volume in order to seek pressure control that is insensitive to the choice of the numerical time step. The resulting method is simple, practical, and efficient. The method is demonstrated through direct numerical simulations of two characteristic model systems-a one-dimensional particle chain for which exact statistical results can be obtained and used as benchmarks, and a three-dimensional system of Lennard-Jones interacting particles simulated in both solid and liquid phases. The results, which are compared against the method of Kolb and Dünweg [J. Chem. Phys. 111, 4453 (1999)], show that the new method behaves according to the objective, namely that acquired statistical averages and fluctuations of configurational measures are accurate and robust against the chosen time step applied to the simulation.
authors.affiliation: Department of Mechanical and Aerospace Engineering, University of California, Davis, California 95616, USA.
authors.forename: Niels
authors.initials: N
authors.lastname: Grønbech-Jensen
authors.affiliation: Department of Biomedical Engineering, Ben Gurion University of the Negev, Be'er Sheva 84105, Israel.
authors.forename: Oded
authors.initials: O
authors.lastname: Farago
mesh_terms: D056004:Molecular Dynamics Simulation; D011312:Pressure; D013696:Temperature