Defect clusters in wustite,Fe1−xO

A quantum chemical approach based on predominantly covalent “normalized ion energies” has been developed for estimating structures and energies for defect clusters in quenched nonstoichiometric wustite (Fe_1?xO). Small defect clusters of zinc blende structure show special stability over other clusters considered. Of these, either a 13:5 or a 16:7 defect cluster (13 or 16 Fe³⁺ vacancies and 5 or 7 tetrahedral Fe³⁺ interstitials) have the proper structure and composition to account for the observed P′ and P″ phases in wustite.     

The observation of a picosecond transient in the relaxation of an iron porphyrin

Iron(III)tetraphenylporphyrin chloride, excited at 353 nm, showed significant bleaching and new absorption at 445 and 55 550 nm, which relaxed in 50 ps. Ground-state recovery occurs in ?100 fs; the bottleneck is populated with 3% efficiency. The photoproduct spectrum resembles a porphyrin ππ^* triplet, and provides evidence for intersystem crossing in an iron heme.