Neutron Compton scattering as a molecular characterization technique: A study on NaHF₂

Inelastic neutron scattering experiments were performed at intermediate and high momentum transfers, up to 85–90 Å⁻¹, to study the proton momentum distribution in polycrystalline sodium hydrogen fluoride (NaHF₂) at low temperature (below 5 K). The H mean kinetic energy was extracted and compared to the results from hydrogen-projected density of phonon states derived from intermediate momentum transfer inelastic neutron scattering and lattice dynamics simulations. A reasonable agreement between the two figures was found. In addition, relevant aspects of high momentum transfer neutron scattering from NaHF₂ were explored in detail, ranging from an alternative evaluation of final state effects to the role played by the instrumental resolution and to the possibility to reconstruct the potential felt by a proton from its momentum distribution.