Datensatz

Zusammenfassung

The symmetry selection rules for the mixing of states by spin orbit interaction are known to cause unequal population of the three electronic levels of excited triplet states in aromatic molecules. It is shown here that the same selection rules, when combined with the hyperfine interaction, can also produce a selective population and depopulation of the nuclear sublevels. This mechanism is proposed to be responsible for the large optical nuclear polarisation (ONP) in low fields observed experimentally.