Effects of surface track potential on secondary electron emission and surface stopping power

In ion-surface scattering a positive surface track potential is induced on the surface behind the projectile due to ionizing collisions. The surface track potential is expected to affect secondary electron emission as well as the energy loss process of the projectile ions. We measure secondary electron yield induced by 0.5 MeV/u H⁺, He²⁺, Li²⁺ and B³⁺ ions during grazing angle scattering at a KCl(0 0 1) surface. The position-dependent secondary electron production rate was derived from the observed secondary electron yield. The secondary electron production rate is normalized by the mean square charge of the reflected ions. The normalized rate decreases with Z₁ suggesting that the surface track potential recapture the secondary electrons. We also measure the energy losses of 0.5 MeV/u H⁺, He²⁺, Li²⁺, B³⁺ and C⁴⁺ ions during grazing angle scattering at a KCl(0 0 1) surface. The observed result suggests that the surface stopping power is reduced by the surface track potential.