Evidence of circular Rydberg states in beam-foil experiments: Role of the surface wake field

Abstract

We have employed the concept of the surface wake field to model the formation of the circular Rydberg states in the beam-foil experiments. The experimental studies of atomic excitation processes show the formation of circular Rydberg states either in the bulk of the foil or at the exit surface, and the mechanism is explained by several controversial theories. The present model is based on the interesting fact that the charge state fraction as well as the surface wake field depend on the foil thickness and it resolves a long-standing discrepancy on the mechanism of the formation of circular Rydberg states. The influence of exit layers is twofold. Initially, the high angular momentum Rydberg states are produced in the last layers of the foil by the Stark switching due to the bulk wake field and finally, they are transferred to the circular Rydberg states as a single multiphoton process due to the influence of the surface wake field.

Theoretical studies on multiple ionization and electron capture processes in heavy ion induced M-shell ionization

“…The contrasting picture between incident charge state and q m inside the target is governed by the ion-solid interaction at the bulk of the target. While the q m for the outside the target is guided by the ion interaction with the solid surface [36][37][38]. In second step, the q m -values inside the target are substituted in the Lorentzian charge state distribution [38] to obtain the F(q) as follows…”

Wake potential in graphene-insulator-graphene composite systems

“…The occurrence of the wake effect was also studied on solid surfaces, both in theoretical works [7,8] and in experiments [9,10], which demonstrated vicinage effects in the Coulomb explosion and energy loss of diatomic molecules grazingly scattered on crystal surfaces. In the more recent experiments, it was shown that the surface wake also plays a role in the energy loss and straggling of fast ions traversing a dielectric boundary [11] and that it affects the formation of circular Rydberg states in beam-foil experiments [12]. While the above studies were concerned with the wake due to electronic collective modes in solids and their surfaces, there were several studies addressing the role of the wake due to the excitation of the Fuchs-Kliewer (FK) or optical surface phonon modes in ion scattering from polar surfaces [13,14].…”