Path dependence of the charge state distributions of low-energy F ions backscattered from RbI(1 0 0)

Projectile neutralization during backscattering from RbI(1 0 0) of F multicharged ions in the keV energy range was investigated utilizing a time-of-flight technique. The energy and charge state distributions of the scattered ions were measured as a function of the polar incidence angle and the target azimuthal orientation. We found significant variations in the neutralization degree for incident projectiles of different charge states. The charge state distribution of scattered ions, including negative charge states, was found to depend on both the polar incidence and azimuthal orientation angles. These variations are attributed to the particular hard and soft encounters with neighboring lattice sites at the target surface along the path of the ion. Sample data for few-keV F²⁺ and F⁷⁺ incident projectiles are presented to illustrate the underlying concepts.