Incoherent neutron scattering by the phonon-libron system in solid ortho-hydrogen

The incoherent scattering cross section of slow neutrons by ortho hydrogen atT=0 K has been calculated for the case where only one excitation (phonon, libron resp. a mixed mode quantum) is created. The results are compared with the experiment of Stein, Stiller and Stockmeyer and prove that only the coupling of phonons and librons can produce the measured cross section.