COMPUTER-SIMULATION OF CRITICAL PHENOMENA IN FLUIDS

We extend to the computer simulation of off-lattice models a phenomeno logical description of finite-size effects, already successfully used in the simulation of lattice systems. The density fluctuations are stu died in subsystems of the simulation cell in the canonical ensemble. T he density distribution functions of the subsystems are analysed by us ing finite-size scaling. Results are presented for the two-dimensional Lennard-Jones fluid with N = 4096 particles. The study of the reduced fourth-order cumulants of the density distribution functions allows u s to obtain the critical temperature and density. We compare the resul ts with previous values obtained by different methods. We show that fi nite-size scaling concepts can be extended to off-lattice models. A mu ch larger computer effort would be necessary, however, in order to get reliable estimates of critical exponents and amplitudes.