Final-state effects in neutron scattering from liquid neon.

Abstract

We report inelastic scattering measurements of the neutron Compton profile, J(y), in liquid Ne, over a broad range of neutron wave-vector transfers for liquid at a density of 36.1 atoms ${\mathrm{nm}}^{\mathrm{\ensuremath{-}}3}$ at 27 K. The measurements used a chopper spectrometer at a pulsed-spallation neutron source. The wave vectors span the range 105 to 276 ${\mathrm{nm}}^{\mathrm{\ensuremath{-}}1}$, a range in which deviations from impulse-approximation scattering are expected to be dominated by final-state effects. Spectrometer resolution and sample-dependent multiple scattering were taken into account using a sophisticated Monte Carlo simulation. The data were analyzed, using the series expansion of Sears, to determine the magnitude of the first antisymmetric term in the expansion as a function of wave-vector transfer. Special care was taken to assess possible contributions arising from systematic errors. We find that the measurements agree very well with a calculation using a pair-distribution function, g(r), from path-integral Monte Carlo simulation of liquid Ne near this density and temperature.