Detection of electrons in the surface ionization of H Rydberg atoms and H2 Rydberg molecules

Abstract

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.