FACULTY COLLOQUIUM: Molecular electronic structure and local environment: a toolbox for nanotechnology

Professor Agostino Migliore (Duke University, Dept. of Chemistry)
Friday, 27 January 2017 - 3:00pm
French Family Science Center 4233

The electronic structure properties of molecules, and their dependence on nuclear motion and external stimuli, offer an extremely rich toolbox to implement reactions and electronic relaxation processes of nanotechnological relevance. Multiple charge transfer is at the core of enzymatic reaction mechanisms; charge relaxation and polarization can enable chemical sensing, as well as enhanced solar energy harvesting; bond breaking and formation, or the effect of conformational changes on electronic structure properties, can be used to produce molecular switches. The first part of this talk highlights possible scenarios for the coupling of inter-domain electron transfer and proton transfer at the core of the catalytic reaction in mononuclear copper monooxygenases. In general terms, our results stress the need to take a more flexible perspective on charge transfer and relaxation in protein environments than it is suggested by standard solution studies of individual amino acids. The electron transfer reaction cannot be simplistically described as a transition between the copper ions, and the acid dissociation constants may fail in predicting proton transfer between residues, due to the strong influence of the local chemical (electronic and nuclear) environment within the protein. The second part of this talk will focus on charge conduction and energy absorption of molecules in contact with graphene and with inorganic materials, or subject to external perturbations such as electrostatic fields. In most of these contexts, the nuclear motion can act either as a determinant or as a perturbation of the required molecular property.