Density dependence of the momentum distributions in liquid para-hydrogen

Momentum distributions of liquid para-hydrogen were determined by means of inelastic neutron scattering under applied pressures ranging from 1 to 80 bars, at T=16.5 K. The data processing procedure involves the parametrization of the dynamic structure factor and yields a set of momentum distributions as functions of the density. The results depict significant pressure dependences for all single-particle quantities such as the momentum distributions and average kinetic energies as well as for the final-state effects. The obtained results enable us to quantify the departure of the momentum distributions from classical Maxwell-Gauss shape. Such observations are then rationalized with the help of calculations that were carried out in terms of the correlated density matrix formalism.