Monte Carlo simulations in multibaric–multithermal ensemble

We propose a new generalized-ensemble algorithm, which we refer to as the multibaric–multithermal Monte Carlo method. The multibaric–multithermal Monte Carlo simulations perform random walks widely both in volume space and in potential energy space. From only one simulation run, one can calculate isobaric–isothermal–ensemble averages at any pressure and any temperature. We test the effectiveness of this algorithm by applying it to the Lennard–Jones 12–6 potential system with 500 particles. It is found that a single simulation of the new method indeed gives accurate average quantities in isobaric–isothermal ensemble for a wide range of pressure and temperature.