Theoretical investigations of the electronic states of porphyrins. III. Low‐lying electronic states of porphinatoiron(II)

Ab initio configuration interaction calculations are reported on the lowest quintet, triplet, and singlet states of Fe II (P). Due to the large number of states found, a catalog of the low‐lying states is presented. Novel triplet and quintet charge‐transfer states are reported as low as 1.3 eV. These states are d 5 ( S = 5/2) on the iron low‐spin‐coupled to the radical anion excited porphyrin ring ( S = 1/2 or 3/2). Oscillator strengths originating from each of three low‐energy triplet states are reported.