Symplectic algorithm for constant-pressure molecular dynamics using a Nose-Poincare thermostat

摘要

We present a new algorithm for isothermal-isobaric molecular-dynamicssimulation. The method uses an extended Hamiltonian with an Andersen pistoncombined with the Nos'e-Poincar'e thermostat, recently developed by Bond,Leimkuhler and Laird [J. Comp. Phys., 151, (1999)]. ThisNos'e-Poincar'e-Andersen (NPA) formulation has advantages over theNos'e-Hoover-Andersen approach in that the NPA is Hamiltonian and can takeadvantage of symplectic integration schemes, which lead to enhanced stabilityfor long-time simulations. The equations of motion are integrated using aGeneralized Leapfrog Algorithm and the method is easy to implement, symplectic,explicit and time reversible. To demonstrate the stability of the method weshow results for test simulations using a model for aluminum.