Critical behavior of simple fluids confined by microporous materials

a cubic lattice with nearest-neighbor interactions. A small fraction of the lattices sites are blocked, thereby creating a quenched matrix. Histogram reweighting techniques are applied to investigate the critical behavior of the system. We have studied lattice sizes ranging from L = 10 to L = 18. Fo r each size, we have evaluated the number of matrix replicas necessary to o btain statistically meaningful results. This number, determined by analyzin g the convergence of the histograms, ranged from 50 for the smallest system sizes to 200 for the largest sizes. We have evaluated the critical tempera ture, the fourth cumulant of Binder et nl. [K. K. Kaski, K. Binder, and J. D. Gunton, Phys. Rev. B 29, 3996 (1984)], and the critical exponents 1/(l ' ) and beta/nu. The estimated critical temperature is only slightly lower th an that of the three-dimensional Ising model. The simulated critical expone nts, however, differ significantly from those for Ising-class three- and tw o-dimensional systems. (C) 2000 American Institute of Physics. [S0021-9606( 00)50445-0].