Phonons, Librons, and the Rotational State J = 1 in HCP and FCC Solid Hydrogen by Neutron Spectroscopy

Abstract

Articles you may be interested inRole of distortion in the hcp vs fcc competition in rare-gas solids Low Temp. Phys. 37, 435 (2011); 10.1063/1.3606459 Broadband rotational resonance in solid state NMR spectroscopy Comment on the stability of fcc and hcp hardsphere solids J. Chem. Phys. 82, 5760 (1985); 10.1063/1.448567 NMR relaxation rate and the libron energy of solid hydrogenTransitions between the rotational states J = 1 and J =0 and the densities of phonon and libron states are investigated by incoherent inelastic neutron scattering at 4.2 and at 1.15°K for several concentrations e of the ortho component. By extrapolation of the observed c-dependent energy of the J = 1 state to c=O and c= 1 the effective quadrupole-quadrupole coupling constant is determined. The observations on the densities of phonon and libron states are compared to theoretical predictions.

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“…) In this work we are concerned with the .high-temperature precursors of the librons, which for brevity we call paralibrons. These excitations are seen in Raman scattering (Silvera et al, 1972) and neutron scattering (Stein et al, 1972) and have important effects in NMR relaxation (Harris, 1970b;Hama and Nakamura^ 1970;Amstutz et al, 1969;Weinhaus et al, 1971). The.…”