Inherent pair correlation in simple liquids

This paper is dedicated to the proposition that liquids possess an inherent packing structure which is determined by their collection of potential energy minima. To reveal the inherent structure in a given thermodynamic state, it is necessary to subject the dynamical system to steepest-descent ‘‘quenches’’ that remove thermal motion and distortion and leave the system in the nearest mechanically stable arrangement. Such a program has been carried out via molecular dynamics simulation on an argon-like system containing 108 atoms. Two thermodynamic states at the same reduced density (ρ*=1.0) were considered, one just above the melting temperature T*m and one at approximately 3.5 T*m . Although the pair correlation functions g(r) in these thermodynamic states differed considerably, those produced by the corresponding sets of quenches gq(r) were virtually identical. The implied inherent structure common to both states appears to be best described in terms of highly defective face-centered-cubic crystalline configurations.