On the use of the Ewald summation in computer simulation

Monte Carlo calculations for the restricted primitive model at a point in the molten salt region have been made using a variety of summation methods. The empirical conclusion is that the Ewald summation is an excellent method for this work. It is shown that it does not produce significantly anisotropic pair distributions. It is shown that unlike some of the other methods considered it does not have a systematic bias towards lower energy for some configurations. It is argued that the shape of its effective pair potential does not lead to distortion of the melt structure. However, an approximate form of the Ewald summation is shown to produce significant distortions of the melt structure for the case examined.