Boundary conditions for Monte Carlo simulation of charged systems

We investigate the effects of a change in external dielectric constant e′ on the properties of a system of charges in periodic boundary conditions. The mean square dipole moment fluctuations of a configuration are shown to depend strongly on e′ in the thermodynamic limit. Simulations of 216 restricted primitive electrolyte particles with e′ = 1 and e′ = ∞ at η = 0·35 and Γ = 2, 5 and 10 are reported and obey the formula for the change in mean square dipole moment fluctuations rather well.