Modelling of EMR data for Fe2+(S=2) ions in a [2Fe-2S] cluster in the reduced ferredoxin

The modelling techniques employed in this study utilize structural data to enable correlation of EMR data – described by the spin Hamiltonian (SH) and optical spectroscopy data – described by the crystal field (CF) Hamiltonian. These techniques enable also to predict magnetic and spectroscopic properties of 3dN ions, especially 3d4 and 3d6 ions, in various systems. Specific applications are considered for [Fe2+ and Fe3+] binuclear centres in [2Fe-2S] cluster in the reduced ferredoxin and related biological molecules. The background for model calculations of the zero-field splitting (ZFS) parameters and/or crystal field parameters and the capabilities of the two major techniques used will be presented in the full paper. Here, we present preliminary results of the microscopic spin Hamiltonian (MSH) modelling for Fe2+ (3d6) ions in the reduced ferredoxin.