Spin and charge distribution in iron porphyrin models: a coupled cluster and density-functional study.
We recently performed detailed analyses of the electronic structure of low-spin iron porphyrins using density-functional theory (DFT). Both the spin-density distributions of the oxidized, ferric forms, as well as the changes in total charge density upon reduction to the ferrous forms have been explored. Here, we compare the DFT results with wave-function theory, more specifically, with the approximate singles and doubles coupled-cluster method (CC2). Different spin states are considered by studying representative models of low spin, intermediate spin, and high spin species. The CC2 calculations corroborate the DFT results; the spin density exhibits the same amount of molecular spin polarization, and the charge delocalization is of comparable magnitude. Slight differences in the descriptions are noted and discussed.
Department of Chemistry, P.O. Box 55 (A. I. Virtanens Plats 1), FIN-00014 University of Helsinki, Finland. mikael.johansson@helsinki.fi
Mikael P
MP
Johansson
Dage
D
Sundholm
D001665:Binding Sites; D003198:Computer Simulation; D007501:Iron / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D011166:Porphyrins / Q000737:chemistry*; D011485:Protein Binding; D011789:Quantum Theory; D013113:Spin Labels; D055672:Static Electricity
D011166:Porphyrins; D013113:Spin Labels; D007501:Iron