Neutron spectroscopy of magnesium dihydride

Inelastic neutron scattering spectra of α-MgH2 powder have been measured at T = 7 K with an energy resolution better than 1.5% using the time-of-flight direct geometry spectrometer SEQUOIA. Based on these spectra, the density g(E) of phonon states in α-MgH2 has been experimentally constructed for the first time. Comparing the available experimental data on the heat capacity of α-MgH2 with those calculated using the obtained g(E) confirmed the good accuracy of its determination.

Research highlights
► α-MgH2 is studied by inelastic neutron scattering (INS) with a good accuracy.
► Density g(E) of phonon states in α-MgH2 is constructed based on the INS results.
► Heat capacity of α-MgH2 at temperatures up to 2000 K is calculated from the g(E).
► The calculated heat capacity agrees within 2.5% with the precise literature data. INS is therefore able to give heat capacity of hydrides with a calorimetric precision.