The measurement of self-diffusion coefficients in liquid germanium using quasielastic neutron scattering

摘要

We measured dynamic structure factors using quasielastic neutron scatter-ing for two liquid germanium samples, one in natural isotope abundance. and a second one with a (nat/173)~Ge isotope mixture which exhibits an order of magnitude larger ratio of incoherent to coherent neutron scattering cross section. In an intermediate q range corresponding spectra exhibit similar quasielastic broadening. We show that the measured quasielastic line originates from incoherent scattering. Coherent contributions appear as an almost energy independent background. From the incoherent quasielastic neutron scattering signal self-diffusion coefficients can therefore accu-rately be derived.