Premium
Theoretical investigations of the electronic states of porphyrins. IV. Low‐lying electronic states of bisammineporphinatoiron(II)
Author(s) -
Rawlings Diane C.,
Gouterman Martin,
Davidson Ernest R.,
Feller David
Publication year - 1985
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560280612
Subject(s) - excited state , singlet state , chemistry , configuration interaction , atomic physics , electron configuration , ring (chemistry) , spin states , ab initio , ion , crystallography , physics , inorganic chemistry , organic chemistry
Abstract Ab initio CI calculations are reported on the lowest quintet, triplet, and singlet states of Fe II (P) (NH 3 ) 2 . The lowest singlet state has strong mixing between the configuration ( d xy 2 ( d π ) 4 and ( d xy ) 2 ( d π ) 3 e g π*. The lowest quintet is mixed between 6 A 1 g ) d π and ( 6 A 1 g )e g π*, where 6 A 1 g refers to the high‐spin ferric configuration. We calculate many low‐energy states as 3 (π→π*) ring and metal triplet and quintet configurations [“triptriplets” and “tripquintets”]. The calculations also show low‐energy charge‐transfer configurations of ring anion excited quartets and ferric quartets and sextets [“quartquartets” and “quartsextets”]. The farthest red x,y ‐polarized bands of the experimental spectra of low‐spin hemoproteins are identified as d xy → e g π* or d π → d z 2mixed with d π → d x 2 ‐ y 2and the z ‐polarized bands are assigned as d π → e g π*. The farthest red x,y ‐polarized bands of the high‐spin hemoproteins are identified as excited quartsextet states. Picosecond transients observed in Fe II (TPP) (pip) 2 are attributed to an initial 1 ( d π → e g π*) state, which inter‐system crosses to high‐spin states that lose one ligand.