On the calculation of dielectric properties from computer simulations

We report a reaction field calculation for Stockmayer particles at reduced density $\text{?}{}^1\text{= 0.8}$, reduced temperature $\text{T}{}^1\text{= 1.35}$ and reduced dipole moment $\text{μ}{}^1\text{= 1.64}$ using a relatively large cutoff distance for the dipolar interaction. The dipole-dipole correlation function is compared with corresponding simulations using truly periodic boundary conditions. The mean square fluctuation of the total dipole moment are shown to exhibit a long period oscillation, precluding a determination of the dielectric constant with an accuracy better than 15%, in a Monte-Carlo calculation of the order of 5 × 10⁶ configurations.