Anharmonic One-Libron Spectrum in Solid H2 and D2

A self-consistent, anharmonic approximation is used to compute the values of the libron energies as a function of the momentum along various symmetry directions in the first Brillouin zone. A density-of-states histogram is also presented, based on a calculation of the libron energies at 584 points in the irreducible section of the first Brillouin zone.