Evidence for Surface-Interaction Effects via a Nuclear Hyperfine-Interaction Experiment

Abstract

A rotation of the perturbed angular correlation of de-excitation $\ensuremath{\gamma}$ rays from $^{18}\mathrm{O}$ nuclei recoiling into vacuum at high velocity has been observed in a tilted-foil geometry. This rotation is due to the polarization of electronic configurations which interact strongly with the nuclear state via the hyperfine interaction. This experiment provides the first experimental evidence for polarization by surface interactions of deeply bound electrons in highly stripped oxygen ions.