CALCULATION OF EQUILIBRIUM ENTROPY DIFFERENCES FROM NONEQUILIBRIUM MOLECULAR-DYNAMICS SIMULATIONS

We present a new simulation technique that can be used to calculate entropy differences between equilibrium states. The method is based on the use of a Gaussian thermostat to continuously move from one equilibrium system to another. When one extrapolates to the infinitely slow limit, the sequence of states so generated are quasi-static states, and the entropy differences can be easily computed form the classical thermodynamic formulae.