THERMODYNAMIC SCALING MONTE-CARLO STUDY OF THE LIQUID-GAS TRANSITION IN THE SQUARE-WELL FLUID

A Temperature-and-Density-Scaling Monte Carlo (TDSMC) study of the squ are-well fluid was carried out. The relative excess free energy was ob tained directly from the simulations with a standard deviation less th en 0.5%. Energy, pressure, compressibility and heat capacity were calc ulated from the excess free energy data. For the system of 256 particl es a reduced density interval of 0.1-0.68 and a reduced temperature in terval of 1.053-1.29 was covered. In the simulations a ''zoom focus'' on the temperature-density grid was used: a ''panoramic view'' of the whole temperature-density region, on a relatively coarse grid, was com bined with a ''close-up'' of the critical-point region, using a finer (T,rho) grid. The coexistence curve was obtained with use of the doubl e-tangent construction on the free energy, and the critical temperatur e and critical density were estimated. The critical parameters found b y the TDSMC method are compared with those of other Monte-Carlo techni ques. (C) 1998 American Institute of Physics. [S0021-9606(98)52403-8].