Then-dependence of electron capture from Rydberg states

Abstract

The cross section, σ n , for electron capture by Na + ions from coherent elliptic states (CES) of Li was studied experimentally. The dependences on the principal quantum number, n, the eccentricity, e, and the spatial orientation of the CES were determined at the two reduced ion velocities v r = 1.20 and 1.68 (v r ≡ v/v e , where v is the ion speed and v e = 1/n the mean electron speed of the CES in atomic units). The ion velocity, v, was perpendicular to the minor axis of the CES throughout the experiment, so the orientation is fully specified by the angle, ϕ, between v and the electric dipole moment, d, of the CES. According to a generalized correspondence principle, the reduced cross section, σ = lim n→∞ σ n /n 4 , is given accurately by classical mechanics, and it is a universal function of the scaled parameters of the collision, which in the present experiment are v r , e and ϕ. It is assumed that this result can be extrapolated to the range of n-values, 20-35, covered in this paper, i.e. σ n = σ • n p where σ and p 4 depend only weakly on n. The experimental data support the assumed existence of a universal cross section function and the expected n 4 -dependence is also confirmed at v r = 1.20, but at v r = 1.68 the n-dependence is closer to n 3 .

Dynamics of a single Rydberg shell in time dependent external fields*

“…The effects of the quantum defect wavefunctions on the non-diagonal terms are found to be negligible, and replaced by analytical values for hydrogen. The quantum defects however do have a significant effect on the dynamics through the diagonal elements of the coupling matrix, given by equation (13). Even quite small quantum defects change the dynamical features completely.…”

“…The experimental arrangement is shown in figure 1. Some parts of it were used earlier in collision experiments with coherent elliptic Rydberg states [12,13]. The set-up and the experimental procedures are described in some detail in the next paragraphs.…”

Charge transfer from coherent elliptic states

“…This, and the minimum quantum fluctuations of CES, make them the natural choice for an experimental study of the GCP. The experimental arrangement allowed a study [45] of the n dependence of CT cross sections for CES under the conditions set forth by the GCP, i.e. constant e and orientation in space of the CES as well as constant reduced velocity, v r = nv.…”