Multibaric-multithermal ensemble simulations for fluid systems

We present new generalized-ensemble molecular dynamics and Monte Carlo simulation methods, which we refer to as the multibaric-multithermal algorithms. The multibaric-multithermal simulations perform random walks widely both in the potential-energy space and in the volume space. From only one simulation run, therefore, one can calculate isobaric-isothermal-ensemble averages in wide ranges of temperature and pressure. We test the effectiveness of this algorithm by applying it to a Lennard-Jones 12-6 potential system.