Temperature dependence of the de Gennes narrowing in liquid rubidium

Abstract

The temperature dependence of the density correlation function at next neighbor distances has been investigated for the liquid metal rubidium. This correlation function is a sensitive parameter for changes in the local structure and its Fourier transform was measured in a coherent inelastic neutron scattering experiment. The zero frequency amplitude related to the long time decay of density fluctuations decreases in a nonlinear way and indicates a change in dynamics around $1.5{T}_{\mathrm{melt}}$. The derived generalized longitudinal viscosity shows a decrease near this temperature. These observations are in agreement with the supposition that solidlike units may melt at this temperature.