The SP-MC computer simulation method for calculating the chemical potential of the square-well fluid

The efficient recently proposed SP-MC method for calculating the chemical p otential of hard-body fluids at very high densities by computer simulation is extended to the case of the square-well fluid. Results are obtained for the square-well fluid with energy width parameter lambda = 1.5. The impleme ntation of the method takes into account a discontinuity in the third deriv ative with respect to core size of the chemical potential at infinite dilut ion of a test particle in the fluid. We note the implications of this disco ntinuity for the SP-MC method for larger values of lambda and for equations of state for square-well fluid mixtures. Chemical potentials have been sim ulated at two high densities over a range of temperatures. We additionally present new simulation results for the compressibility factor and the inter nal energies of the fluid at these state points, and perform thermodynamic consistency calculations involving these quantities and the chemical potent ials. The results are also compared with those of a recently-published equa tion of state.