[3] Modern investigations using pump-probe experiments show molecular pathways – e.g. dissociation of (NO)2 – via these special states.
[4] Rydberg series describe the energy levels associated with partially removing an electron from the ionic core.
Each Rydberg series converges on an ionization energy threshold associated with a particular ionic core configuration.
Wave functions of high Rydberg states are very diffuse and span diameters that approach infinity.
[attribution needed][vague] As a result, any isolated neutral molecule behaves like a hydrogen-like atom at the Rydberg limit.