METHODS OF SINGLE-STEP AND MULTISTEP PARTICLE SWITCHING IN SIMULATIONS OF MIXTURES

In an earlier paper, we applied a procedure combining the energy diffe rence method with a modified Kirkwood-Buff fluctuation theory to extra polate chemical potential differences in three directions (T, P, x). T he results showed that the extrapolations in pressure and concentratio n were successful and the linear temperature extrapolations were moder ate in determination of the phase separations. In this paper we have t ried to calculate the second order of the temperature dependence of th e chemical potential difference using the energy difference methods of single-step and multistep switchings. Due to large fluctuations in ca lculation of the second orders, the method can only predict qualitativ ely or semiquantitatively the second-order terms.