Charge transfer from coherent elliptic states

We present experimental data on charge transfer from coherent elliptic states of Rydberg atoms, which are oriented relative to the impact velocity vector of monoenergetic, singly charged ions. The data cover a broad range of scaled velocities around unity, selected angles of approach over the whole sphere, all eccentricities from zero to one and principal quantum numbers ranging from n = 20 to 35. The cross sections show good qualitative agreement with classical trajectory Monte Carlo calculations, but clear deviations are also observed. (topical review)