Density evolution of the atomic momentum distribution in liquid and solid hydrogen

The density evolution of the atomic momentum distribution has been measured in liquid and solid hydrogen at constant temperature T = 20.4K and in the pressure range between 0 and 1180 bar. The experiment was carried out on the eVS spectrometer, at the pulsed neutron source ISIS, where the energy range of the available neutrons allows one to look directly at the proton wave function. The resulting kinetic energy of the protons is checked against other experimental results where the kinetic energy of centers of mass was measured.