2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/140931We calculate the temperature dependence of NMR relaxation rate and electrical resistivity for coupling to a local, strongly anharmonic phonon mode. We argue that the two-phonon Raman process is dominating NMR relaxation. Due to the strong anharmonicity of the phonon an unusual temperature dependence is found having a low temperature peak and becoming constant towards higher temperatures. The electrical resistivity is found to vary like T^2 at low temperatures and following a sqrt{T} behavior at high temperatures. Both results are in qualitative agreement with recent observations on beta-pyrochlore oxide superconductors.4 pages, 4 figures; new version with some minor additional clarifications; accepted for publication in Phys. Rev. LettSuperconductivityMaterials Sciencetext