PES/DFT studies on electronic structure contributions to electron transfer

The theme of this project is to apply variable energy photoelectron spectroscopy (PES) combined with DFT define electronic structure contributions to electron transfer (ET) in biological systems. Our general approach is to pursue spectral studies on model complexes of heme sites and the iron sulfur clusters using the methodology (VBCI model and DFT calculations) developed in the studies on [FeCl₄]^2-/1- and [Fe(SR)₄]^2-/1- (R= Ph).

The geometric and electronic structure of Cu_A sites

The purple Cu_A site is found in subunit II of cytochrome c oxidase. This site accepts electrons from cytochrome c, and donates them to the heme a group and the binuclear heme a3-Cu_B center located in subunit I. The other enzyme known to contain a Cu_A site is nitrous oxide reductase, where it transfers electrons to the catalytic Cu_Z site.

My studies now focus on perturbed forms of the Cu_A center which can affect the π_u/σ^*_u energy splitting and the extent of localization, tuning the redox properties of this site. This research will provide insight into the potential energy surfaces, the extent of delocalization and the possible contribution of a low-lying excited state to ET by Cu_A.