Noun
Rydberg atom (plural Rydberg atoms)
(physics, chemistry) Any atom which has a single valence electron in a shell well outside any other electrons in the aton; approximates the hydrogen atom.
But the motion of an inflated electron in a Rydberg atom is much slower: it can be controlled with carefully directed nanosecond electric-field pulses, which allow researchers to herd the electron cloud by knocking it back and forth. Source: Internet