Singlet oxygen - Singulettsauerstoff

In this experiment, an excited form of oxygen is presented. This singlet oxygen exists as metastable compound, because the occupation of its antibonding π-Orbitals is against Hund’s rule, which describes degenerate orbitals to be filled up first, with all parallel spins (such as all “up“), and afterwards the antiparallel spin (in this case “down“) electrons. Therefore it is necessary, to “force“ the oxygen in this state, by using other rules of quantum mechanics (consistence of spins on both side of the rea