Bonding in the oxo ferrous iron species: A complete active-space self-consistent-field theory verification of the molecular-oxygen-like pattern

摘要

The bonding of atomic oxygen to ferrous iron was studied using the Fe(OH)_2 system as a model of the ferrous iron center. All lowest triple, quintet, and septet states of OFe(OH)_2 were studied at the complete active-space self-consistent-field theory level augmented by multireference second-order-perturbation theory. In addition the density functional theory with three-parameter exchange functional of Becke and correlation functional of Lee, Yang, and Parr has been applied to this system. The ground state has been found to have ~5A_1 symmetry. The electron configuration responsible for this state is similar to that of molecular oxygen: there are the doubly occupied sigma and pi shells and singly occupied pi~* orbitals. The only difference revealed in this study is the presence of nonbonding half-filled d_(delta) orbitals.