We have investigated the exit charge state distribution of 1-30 keV H, He, C, N, O, Ne and Ar ions that transit ultrathin carbon foils (average thickness of approximately 44 Å). The empirical charge state distribution are used to examine the ratio of the electron loss cross section σl for neutrals to the electron capture cross section σc for positive ions. The ratio, σ/σc, is shown to have a quadratic dependence on the projectile velocity and inverse dependence on Z 2 3 where Z is the projectile atomic number. The data is fit to the equation A(EF-ET)/mZ 2 3 where EF is the exit projectile energy, m is its mass, and A and ET are constants. A pronounced shell effect is observed: the constant A is dependent on the principal quantum number of the projectile, and ET exhibits variations with the projectile outer shell electronic structure.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics