CONFIGURATIONAL TEMPERATURE - VERIFICATION OF MONTE-CARLO SIMULATIONS

A new diagnostic that is useful for checking the algorithmic correctne ss of Monte Carlo computer programs is presented. The check is made by comparing the Boltzmann temperature, which is input to the program an d used to accept or reject moves, with a configurational temperature k (B)T(config) = \del(q)Phi\(2)/del(q)(2)Phi. Here, Phi is the potential energy of the system and del(q) represents the dimensionless gradient operator with respect to the particle positions q. We show, using a s imulation of Lennard-Jones particles, that the configurational tempera ture rapidly and accurately tracks changes made to the input temperatu re even when the system is not in global thermodynamic equilibrium. Co ding and/or algorithm errors can be detected by checking that the inpu t temperature and T-config agree. The effects of system size and conti nuity of Phi and its first derivative on T-config are also discussed. (C) 1998 American Institute of Physics. [S0021-9606(98)52640-2].