Ionisation of Rydberg atoms colliding on metal surfaces

Jelena Sjakste, Andrei G. Borisov, J.P. Gauyacq

Uwe Wille

Mike Kohlhoff

The interface of neutral Rydberg atoms in the gas phase with a solid surface is of interest in many fields of modern research. This interface poses a particular challenge for any application in which Rydberg atoms are close to a substrate but also opens up the possibility of studying properties of the surface material itself through the atomic response. In this review the focus is on the process of electron tunneling from the excited state into the substrate that occurs when a Rydberg atom is located in front of a surface at a range of a few hundred nm and is demonstrated with a metallic surface. It is shown how variations in this ionisation mechanism can provide a powerful tool to probe image-charge effects, measure small superficial electric stray or patch fields and how charge transfer from the Rydberg atom can be in resonance with energetically discrete surface states.

A. A. Mihajlov, R.K. Janev

Using the resonant internal energy conversion mechanism for inelastic atom-Rydberg atom slow collisions, the energy spectra of ejected electrons and the rate coefficients for the ionisation process are calculated analytically. Reaction rates for H*(n)+H, Cs*(n)+Cs, Rb*(n)+Rb and K*(n)+Rb colliding systems are calculated and compared with the available experimental data.

Elin A. McCormack, E. So, Mark Dethlefsen +2 more

The detection of electrons from the surface interaction of Rydberg hydrogen atoms and molecules at a metal surface is investigated experimentally for the first time. The experimental detection of an electron signal in a time gate corresponding to when the Rydberg atoms or molecules are expected to collide with the surface provides evidence for the previously proposed backscattered electron loss (So et al 2009 Phys. Rev. A 79 012901) as a route of surface ionization under electron-extraction fields. Comparison of the ion- and electron-extraction results shows that the dynamics as the Rydberg states approach the surface are very different in the two cases, leading to the possible loss of control of the electronic polarization in the initially prepared Rydberg state from the traversal of level crossings during the Rydberg trajectory. The difference in the ionization dynamics observed for the Rydberg H and H2 cases also illustrates some of the fundamental differences between atomic and molecular, and hydrogenic and non-hydrogenic systems.

James Veale