David N. Beratan of Duke University is supported by the Theoretical and Computational Chemistry Program to design, analyze and interpret inelastic electron-transfer kinetics in molecules with bridge-localized vibrational modes. He is developing interpretive and predictive descriptions of intramolecular inelastic electron-tunneling in a variety of molecules containing an electron donor, a rigid bridge, and an electron acceptor. This work is in collaboration with the experimental group of Rubtsov at Tulane to examine analogies between the double slit electron transmission experiment and the molecular electron-transfer problem. The goal is to define new schemes to control electron transfer and to develop approaches to manipulate the strength of molecule-mediated electronic coupling. This work is having a broad impact in developing intuition that may lead to applications in optical communication and solar energy harvesting. The PI is promoting science education by providing summer research opportunities to economically disadvantaged and historically underrepresented groups. A new course cluster for first-year students is under development to examine the fundamental philosophical foundations of science.
The flow of charge at the scale of atoms and molecules is essential for the proper functioning of biological strucutres and electronic devices. For these structures to perform well, charge must arrive at specific molecular locations at the propert time and in the appropriate amount. This basic research project has explored how the rate of charge flow at the scale of billionths of meters - the molecular scale - is influenced of the vibrations of chemical bonds. We have developed both quantum mechanical theories and, in collaboration with our experimental coworkers, experiments that examine how chemical bond vibrations influence the flow of electronic charge through molecules. In these studies, the dual wave-particle nature of electrons is paramount, and we find that the exchange of energy between electrons and chemical bond vibrations can cause significant changes in the rate of charge flow through molecules. This discovery is significant, as it may allow us to direct and to redirect the flow of charge in molecules to assist in the development, in the long run, of molecular size electronic devices, improved schemes for converting the energy of sunlight into electricity, and a deeper understaning of the molecular origins of disease. We have also been deeply involved in the development of new instuctional courses at the undergraduate and the graduate levels. These include new courses in science ethics, a course in quantum dynamics, and a course in the theory of electron-transfer reactions. We are strongly engaged in the training of graduate students and post-doctoral associates, many of whom have now entered the work force. We also work closely with high school students from disadvantaged backgrounds who perform summer research in our laboratories. Many of these students are now pursuing undergraduate and graduate studies in the sciences.
