The populations of Rydberg states of ions emerging from solid surfaces

Abstract

Analysis of decays of Rydberg ions produced in beam-foil conditions shows that populations are observed to emerge in the form n−β, where n is the principal quantum number and the index β is significantly less than the value 3 expected from most capture models. For 130 MeV Br ions excited by carbon, the high-angular-momentum (l) cascade may be described by β = 3 with a truncated l-value, but a direct cascade, with l = 0, requires β = 2.4. A calculation is described of the effects of the in-target stopping powe causing a change of the initial population via Landau-Zener type level anticrossings. Evidence is shown that the low-l population does suffer