Rydberg state

An @ET07026@ that arises by the excitation of a @V06588@ electron to a diffuse atomic-like orbital. For instance, the lowest lying Rydberg state (n, 3S) of NH3 can be described as resulting from the excitation of a non-bonding orbital to a 3S @R05431@.
PAC, 1999, 71, 1919. (Glossary of terms used in theoretical organic chemistry) on page 1961 [Terms] [Paper]