Velocity correlations in supercooled and nucleated liquid rubidium

Abstract

The momentum transport is studied for supercooled liquid rubidium, via molecular dynamics. The transport is investigated on a microscopic scale by measuring the contribution to the two point velocity correlation function for various separations of the two points. The correlation functions are measured in both the normal and supercooled liquid and the solid phase. It is found that momentum is transported by two different mechanisms; by correlated oscillations associated with the maximum of g(r), and by strongly diffusive modes associated with the minimum of g(r). The amplitude of the diffusive or liquid-like mode increases upon nucleation, and remains large at low temperatures in the solid phase.