Finite-size dependence of the bridge function extracted from molecular dynamics simulations

The bridge function for liquid sodium at T5373 K is obtained by using the mean spherical approximationto extrapolate the pair distribution function ~PDF!, calculated in molecular dynamics ~MD! simulations, beyondthe half simulation box length for two sizes of the MD system. The bridge function is found to stronglydepend on the total number of particles used in the simulation cell. This dependency leads to a spuriousmaximum of the static structure factor at long wavelengths, obtained from the reference hypernetted-chainapproximation ~RHNC! with the MD system used as a reference system ~RHNC-MD!. A simple self-consistentprocedure, proposed to account for the finite-size effects in the bridge function, allows one to efficiently correctthe RHNC-MD static structure factor for all unphysical manifestations