Quasi-elastic thermal neutron scattering data on SrCe0.95Yb0.05H0.02O2.985 were used to extend a 2-state model for proton diffusion in this compound. The first state involved the free diffusion of protons which jumped from O atom to O atom; forming OH-. The second state involved protons which were trapped at low-energy sites near to a Yb3+ ion on a Ce4+ site. This model was here supplemented with a very fast localized motion which occurred, in the first state, as a reorientation of OH- ions. This motion was visible as a broad quasi-elastic component in the neutron energy spectra, and had a very low activation energy.

T.Matzke, U.Stimming, C.Karmonik, M.Sötratmo, R.Hempelmann, F.Guethoff: Solid State Ionics, 1996, 86-88[1], 621-8