Optical parameter values of the Ewald method with electrostatic layer correction for Coulomb interactions in slab geometry

The Ewald type methods used in computer simulations of charges in a system with 2D periodicity are compared with the Ewald method with electrostatic layer correction (ELC) analysing numerical errors for charges in a cubic box. For the Ewald method with ELC a procedure to determine values of the method parameters, which give required accuracy of calculations, is presented. To find out optimal values of the convergence parameter, and real- and reciprocal-space cut-off radii the summation errors for conventional Ewald method can be applied and the ELC error gives possibility to choose a gap of an empty space in the simulation box. The correctness of the procedure is proved in test numerical calculations for charges distributed uniformly in a cubic box and charges located in two layers near the box basis.