0 Using mean field theory to determine the structure of uniform fluids

The structure of a uniform simple liquid is related to that of a reference fluid with purely repulsive intermolecular forces in a self-consistently determined external reference field (ERF) φR. The ERF can be separated into a harshly repulsive part φR0 generated by the repulsive core of a reference particle fixed at the origin and a more slowly varying part φR1 arising from a mean field treatment of the attractive forces. We use a generalized linear response method to calculate the reference fluid structure, first determining the response to the smoother part φR1 of the ERF alone, followed by the response to the harshly repulsive part. Both steps can be carried out very accurately, as confirmed by MD simulations, and good agreement with the structure of the full LJ fluid is found.