Rydberg atoms

Abstract
Recent investigations of Rydberg atoms are described in an effort to give a picture of their properties, many of which can be understood from the behaviour of the Coulomb radial functions. The authors begin by a discussion of Coulomb wavefunctions, and progress to a description of the energy level structure. The behaviour of Rydberg atoms in electric fields is discussed to provide an understanding of the phenomenon and to show how electric field ionisation may be used as a tool in a wide variety of experiments. Unique opportunities to study the interaction with black-body radiation and vacuum fluctuations are discussed. A survey of the broad range of Rydberg atom collisions, with ground-state atoms and molecules, charged particles and other Rydberg atoms, is presented to show the different physical interactions responsible. This is followed by a brief summary of the study of autoionising Rydberg states, a stepping stone toward the elusive 'double Rydberg' atom. Finally typical experimental procedures are described.