A molecular dynamics study of structure and dynamics in high-density liquids

Abstract

By means of molecular dynamics simulations we have investigated increasing configurational ordering and decreasing particle mobility with increasing density ρ of a three-dimensional equilibrated liquid composed of soft discs. The equal-time correlation function h ⁽ⁿ⁾ ₃ (0) which includes two-, three- and four-body correlations is introduced as a measure of structural order; this function is related to the dipole-induced-dipole equal-time correlation function and its sensitivity to structural order in the liquid is associated with the cancellation effect, i.e. the cancellation of the positive contributions of the two- and four- body correlations by the negative contribution of the three-body correlations. The analogous time-dependent correlation function h ⁽⁴⁾ ₃ (t) is also studied. The possible implications of these results to the study of supercooled liquids and glasses is discussed.