Observation of Fano Profiles in Photoionization of Rubidium in the Presence of a dc Field

Abstract

We report the observation of Fano profiles in the $\ensuremath{\pi}$-photoionization spectrum of atomic rubidium in the presence of a dc field. Such an observation has been made possible thanks to the use of very high-resolution techniques. It can be considered as an experimental proof of the validity of the "nonhydrogenic" process suggested recently to explain ionization in a static electric field for all atoms except hydrogen.