Localized modes of oscillation in hydrogen and deuterium doped lead

Abstract

We have measured the tunneling characteristics of quench-condensed films of pure Pb, hydrogen-doped Pb, and deuterium- doped Pb. We have determined phonon spectra to fit the electronic densities of states calculated from our data. The phonon spectra for Pb/H and Pb/D exhibit additional phonon peaks which we associate with a localized mode (or modes) of the impurity. The magnitudes of the peaks indicate that this mode is strongly coupled to the electronic system.