We report on measurements of the hollow atom dynamics on a clean and LiF covered Au(111) surface. The $\mathrm{KLL}$-Auger spectrum arising from grazing incidence 6 keV ${\mathrm{O}}^{7+}$ projectiles is monitored as a function of the LiF coverage up to 1 monolayer. As the coverage increases, we observe a strong reduction in the above-surface component of the $\mathrm{KLL}$-Auger emission. The astonishing similarity, with respect to $\mathrm{KLL}$-Auger emission, between a single LiF monolayer on Au(111) and a LiF bulk surface, indicates that the large band gap of the latter is not the limiting factor in the neutralization of highly charged ions.

• Received 24 December 1997

DOI:https://doi.org/10.1103/PhysRevLett.81.1219