Finite-size effects in molecular dynamics simulations: Static structure factor and compressibility. I. Theoretical method.

A method is presented for determining the static structure factor S(Q) of a uniform bulk fluid, for all wave-vector magnitudes Q, from computer simulation data for a finite (N-particle) system. The method is based on the usual Fourier transform relation between S(Q) and the radial distribution function g(r) and on the theory of explicit finite-size effects, in particular a Taylor-series expansion, in powers of 1/N, for ${\mathit{g}}_{\mathit{N}}$(r), the N-particle counterpart of g(r). A time-dependent generalization of the method to the intermediate scattering function I(Q,t) is also presented. Implicit finite-size effects are also considered, but are found to be negligible for systems to which we have applied the method. \textcopyright{} 1996 The American Physical Society.