Kenneth Jordan of the University of Pittsburgh is supported by an award from the Chemical Theory, Models and Computational Methods program for research to develop theoretical methods for understanding hydrated electrons and ions in water. The work is producing an enhanced understanding of the behavior of excess electrons in hydrogen-bonding solvents and of the role of weak interactions on the properties of water at interfaces.
Many important chemical and biological processes, including electrochemical processes and electron transfer in photosynthesis, are driven by excess electrons in the presence of water. Despite the large number of experimental and theoretical studies of the hydrated electron and of the excess electron attached to water clusters, a comprehensive understanding of the structures and dynamics of these species is lacking. The theoretical studies being carried out by the Jordan group employ state-of-the-art electron-water and water-water potentials to simulate negatively-charged water clusters of a larger size than has been possible in the past. The work also includes two projects that advance knowledge in the area of weak interactions. The first of these involves the development of new methods of correcting density functional theory for long-range interactions, while the second involves the development of accurate potentials describing the interaction between a water monomer and the graphite surface. The ultimate goal of this project is to perform simulations of water on graphite surfaces and confined in carbon nanotubes using the newly developed, accurate force fields. The work is having a broader impact on many fields of science and its impact is further broadened through the PI's extensive educational and outreach activities with the Telluride Science Research Center.
This project has developed and used computational methods to provide an enhanced understanding of how excess electrons are accommodated by water and other chemical species and to characterize the adsorption of water on graphitic surfaces. The former results are relevant to areas ranging from electrochemistry, to photosynthesis, and to new types of electronic devises. The latter studies provided new insights into the nature of the interaction of water with surfaces in general. The results of high-level electronic structure calculations were used to design one-electron models which have allowed treating much larger systems. Improved methods for describing the long-range quantum mechanical interactions between molecules were also developed. Five graduate students associated with the project got their degrees (four Ph.D.s and one M.S.) over the past three years. In addition, three postdoctoral fellows and one undergraduate student worked on the projects. The students and postdoctoral fellows acquired skills in developing and applying computer simulations methods to address challenging problems. Two of the group members working on the NSF-supported projects were women. The project has involved collaborations with scientists in Germany and England as well as at several other institutions in the United States. The results of the research have been communicated in journal articles and in invited talks at major national and international meetings. In addition, our accomplishments on the research front have led to opportunities to deliver lectures at educational/training workshops for graduate students as well as at workshops with many of the attendees being outside my field. These include being a lecturer at a workshop at the Institute for Pure and Applied Mathematics, at UCLA, delivering four lectures at a workshop on Computational Chemistry held at Peking University, and giving a lecture at a workshop held at the Institute for Theoretical Atomic and Molecular Physics, Smithsonian Institute.
