DENSITY EVOLUTION OF THE ATOMIC MOMENTUM DISTRIBUTION IN LIQUID AND SOLID HYDROGEN

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