ISOTHERMAL ISOBARIC MOLECULAR-DYNAMICS SIMULATIONS WITH MONTE-CARLO VOLUME SAMPLING

A new pressure coupling method is described that combines Monte Carlo volume-space sampling with traditional molecular dynamics calculations to simulate the physical properties of molecular systems under standard conditions. The pressure is maintained by accepting or rejecting volume moves of newly propagated configurations using the Metropolis algorithm with probability P(Delta V) = min(1, exp((-1/kT(0)){Delta E + P-0 Delta V - NkT(0) In[(V + Delta V)/V]})). The sample is further coupled to an external temperature bath using a variation of Andersen's stochastic collisions. The computational approach was implemented and applied to simulate the equilibrium properties of dense neon at various pressures. The results show the method to be both reliable and efficient for maintaining isothermal-isobaric conditions and should prove effective for studying the pressure dependence of physical properties in molecular systems.