Tunneling Pathways: Our tunneling pathway model for protein electron transfer reactions provides a framework for understanding the dependence of these rates on 3D structure. Ongoing studies of macromolecule electron transfer are aimed at: (1) determining the differences between DNA and protein electron transfer; (2) understanding how proteins control intermolecular (protein-protein) electron transfer; (3) obtaining "ab initio quality" estimates of donor-acceptor interactions in proteins and DNA via molecular fragment approaches and large scale self-consistent field computations.

Biological energy transduction: We are exploring the molecular mechanisms that explain how the energy of biological transmembrane electrochemical gradients is captured and converted (by ATP synthase) into discrete energy-storing chemical bonds. We are also examining how the energy stored in ATP is later extracted in biosynthesis to drive, for example, electron transfer in proteins like nitrogenase.

Multi-electron catalysis: Many catalytic processes in biology involve the delivery of multiple electrons. investigation of multi-electron redox events are underway, with the aim of understanding the activation of small substrates (N2, CO2, etc.). Our present goal is to determine the regimes and activation barriers for sequential, concerted, or intermediate electron transfer processes.

Molecular-scale materials design: A new direction of our research focuses on the intersection of chemistry and micro/nano-electronics (in collaboration with Dave Waldeck at the University of Pittsburgh and Ron Naaman at the Weizmann Institute). We are exploring the chemical control of electron flow through two novel hybrid electronic devices: molecular controlled semiconductor resistors and negative differential resistance devices. We are also exploring the transmissio of spin-polarized electrons through molecular films.

Assignment of absolute stereochemistry by computation: In another exciting interdisciplinary collaboration, we have joined forces with the Wipf group (University of Pittsburgh) for the computational assignment of relative and absolute stereochemistry in complex organic molecules. Recent developments have enabled the detailed probing of how molecular conformational influences optical rotation, and how specific chemical groups influence the optical rotation. In addition to expanding the methodologies, we are now exploring the nature of optical rotation in oriented media, to supplement earlier studies of isotropic solutions.