Dielectric properties and the convergence of multipolar lattice sums

A trivially modified version of Ladd's multipole expansion of dipolar lattice sums (equivalent to an Ewald sum) is tested in a series of computer simulations. For bulk dielectric properties the expansion converges very quickly, and the results are identical to reaction field calculations. Microscopic orientational correlations converge somewhat less quickly, but for a system of point dipoles the limiting structure is only marginally different from reaction field simulations with ϵRF = ∞.