Formation of Rydberg states in fast ions penetrating thin carbon-foil and gas targets

Abstract

The absolute field-ionization yields of gas- and foil-excited Rydberg states are measured for different fast beam ions. From the yields a direct comparison of the quantum-state populations of high-n states (n>100) produced by gas and foil excitation could be obtained. Model calculations are consistent with the high-n states being predominantly produced by excitation of the projectile or capture of target electrons in the last layers of the solid target.