Yirong Mo of Western Michigan University is supported by an award from the Chemical Theory, Models and Computational Methods program to develop methods for studying intra- and inter-molecular electron transfer processes. A focus of the research is the development of the general block-localized wave function method which combines the advantages of both molecular orbital and valence bond theories, and thus can be regarded as the simplest variant of valence bond theory. A key issue in this project is the more flexible definition of blocks for the expansion of orbitals. Professor Mo and his coworkers are developing new approaches for elucidating the mechanism of proton-coupled electron transfer between an acylamide unit and its oxidative lesion-generated radical, the electrophilic aromatic nitrosation and nitration reactions and the origin of the anomeric effect which plays a central role for carbohydrates. The researchers are also exploring the protein secondary structural and conformational effects on long-range electron transfer using polypeptide model systems such as oligoglycines, by computing the critical quantities such as electronic coupling energy and reorganization energy.
These novel computational methods enable calculation of electronic wave functions that provide direct and quantitative insight into chemical bonding in a large variety of molecular processes. This is important in many applications throughout chemistry, biochemistry and engineering. A ubiquitous example arises in processes involving transfer of electrons, such as photosynthesis and aerobic respiration and DNA repair, for which these tools allow investigating the electronic and structural factors that regulate electron transfer rates and efficiencies. The algorithms and software being developed will be of value for interpretation of experimental data and for education and training of postdocs, graduate students and undergraduates. This is enabled in part by Professor Mo's co-directorship of the Computational Modeling and Simulation Lab at Western Michigan University, in which capacity he also provides demonstrations and talks to Kalamazoo high school students.
