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Net spin and polarization components of the spin density for the single determinant in the basis of paired orbitals
Author(s) -
Ruzankin Sergey Ph.,
Lyskov Igor,
Zilberberg Igor L.
Publication year - 2012
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.24228
Subject(s) - spin polarization , atomic orbital , chemistry , basis set , density functional theory , molecular orbital , diamagnetism , spin (aerodynamics) , molecular physics , atomic physics , condensed matter physics , physics , electron , computational chemistry , quantum mechanics , molecule , magnetic field , organic chemistry , thermodynamics
A decomposition of the spin density into the net spin density and polarization density for the unrestricted Kohn–Sham (KS) determinant in the basis of Löwdin–Amos–Hall paired orbitals (PO) is derived. In PO basis set, the net spin part of spin density is only determined by the manifold of occupied α‐spin orbitals which do not overlap with occupied β‐spin orbitals. In its turn, the polarization part is associated with the pairs of overlapping α and β orbitals. The decreased overlap in these pairs corresponds to the increased degree of spin polarization. As an example of the developed spin density decomposition, the complex of FeO with nitrobenzene (taken in the state with spin projection of S z = 2) is considered for the B3LYP solution revealing substantial spin contamination for the KS determinant. The spin density decomposition predicts for this complex appreciable polarization density over the whole complex while the net spin density remains counter intuitive almost intact at FeO center. This result changes presumed mechanism of metal‐to‐ligand transfer of unpaired electrons from paramagnetic center to diamagnetic ligand having a high electron affinity. © 2012 Wiley Periodicals, Inc.