A method for the extrapolation of pair distribution functions

A method is presented for the extrapolation of distribution functions obtained from Monte Carlo or Molecular Dynamics simulations. The procedure assumes a zero direct correlation function at large interparticle separations. It does not require a detailed knowledge of the potential or resort to approximate integral equations of the Percus-Yevick type. An algorithm is defined for choice of the cut-off in the input data which produces continuity between the extrapolated and original data. The procedure is tested and shown to be successful on a matched pair of known direct and total correlation functions. It is then applied to a pair distribution generated by Molecular Dynamics for a 12-6 potential.