Density and temperature dependence of the structure factor of dense fluid helium

Abstract

The authors measured the static structure factor S(k) of dense fluid helium by neutron diffraction as a function of density (at fixed temperature T=13.3 K) and as a function of temperature (at fixed number density n-18.7 nm-3). They give the results and calculate the density derivative at T=13.3 K; n=22.0 nm-3. They use this density derivative, which is determined by the triplet correlation function g3(r,s), to test the proposal for g3(r,s) made by Winfield and Egelstaff. They find that this proposed form of g3(r,s) gives a reasonable prediction for the experimental derivative. Hence, they use this proposal to estimate the square of the energy-density correlation function at equal times, l2(k), from experiments, using the temperature derivative at n=18.7 nm-3 and T=13.3 K.