Neutralization rate for slow Ar+ ions in front of KCl(0Â 0Â 1)

Charge state distributions of reflected ions are measured when 5 keV Arq+(q = 0−2) ions are incident on a clean KCl(0 0 1) surface at grazing angle, θi. Although the charge state distribution does not depend on the incident charge state at larger θi, significant dependence of the charge state distribution on incident charge state is observed at smaller θi. The ionization of Ar0 is completely suppressed at θi < 20 mrad, while large neutralization probability is observed for Ar+ incidence. These features allow us to derive the position-dependent neutralization rate of Ar+ in front of KCl(0 0 1). The obtained neutralization rate decreases exponentially with distance from the surface as it is usually assumed.