Viscoelastic behavior of helium at 39 K and 114 bar.

Abstract

The dynamic structure factor S(k,\ensuremath{\omega}) of dense helium at 39.3 K (\ensuremath{\simeq}8${\mathit{T}}_{\mathit{c}}$) and 114 bar is measured by inelastic neutron scattering for wave numbers 3\ensuremath{\le}k\ensuremath{\le}24 ${\mathrm{nm}}^{\mathrm{\ensuremath{-}}1}$. In contrast to dense noble-gas fluids at T2${\mathit{T}}_{\mathit{c}}$, the present S(k,\ensuremath{\omega}) can be described completely by the viscoelastic model, in which S(k,\ensuremath{\omega}) is determined for each k by its zeroth, second, and fourth frequency moment and by one decay rate (that of the microscopic momentum flux).