Copper spin-coupling model

The simulated spectra in Figure 18 represent a series of replicate ESEEM experiments performed on a system containing a single Cu- N interaction with a Fermi contact interaction energy of 26 MHz and quadrupole coupling (e Qqzz) of 3.5 MHz. It is immediately evident from these simulations that the behavior observed at the X-band is reproduced at the W-band provided that the spin-Hamiltonian model that is used to describe experiments at the X-band is not affected in the extremely high magnetic fields of the W-band i.e., no introduction of nonlinear effects). The W-band ESEEM spectra of the Type I copper center of azu-... 

Nitrosyl complexes of both S = and S = are common. The S = nitrosyl complexes or iron and copper have slightly anisotropic g tensors (Ag/g < 2) with the anisotropy provided primarily by contributions of orbital angular momentum from the metal d orbitals. As an example, we consider the model proposed by Kon and Katakoa (1969) for ferroprotoheme-NO complexes, which is also applicable to the ferrous-nitrosyl complexes of heme proteins. In the complexes studied by these workers, the axial ligands are a nitrogenous base and NO. They proposed that the unpaired electron resides primarily in the metal d z orbital. The spin-orbit coupling would then mix contributions from the d, and dy orbitals. 

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