Energy loss in large-angle scattering of slow, highly charged Ar ions from a Au surface

Abstract

Energy loss of slow ($v\ensuremath{\approx}0.06 \mathrm{a}.\mathrm{u}.$), highly charged ${\mathrm{Ar}}^{9+}$ ions scattered from a Au(111) single-crystal surface has been investigated for different incident angles ($\ensuremath{\psi}=5\ifmmode^\circ\else\textdegree\fi{}$ and $37.5\ifmmode^\circ\else\textdegree\fi{}$) and a fixed scattering angle of $75\ifmmode^\circ\else\textdegree\fi{}.$ The energy position of the elastic peak agrees well with the value expected for the binary elastic scattering. At small incidence angle $(5\ifmmode^\circ\else\textdegree\fi{})$ an additional inelastic energy loss was identified in spite of the large scattering angle. This additional energy loss is found to compare well with a combination of a modified Firsov model with processes of electron capture, recapture, Auger transitions, and image charge acceleration during the ion-surface interactions.