Kenneth D. Jordan of the University of Pittsburgh is supported by an award from the Theoretical and Computational Chemistry program to continue his research on understanding the connection between localization of the proton defect and strong anharmonic effects in the vibrational spectra of protonated water clusters and excess electron-water cluster systems. Improved models for exploring the potential energy surfaces and for carrying out simulations on protonated water clusters are being developed. The Drude-model for treating the interaction of an excess electron with clusters of polar molecules that was developed during the previous award is being modified to permit its use in simulations of clusters containing twenty or more water molecules and will be combined with more sophisticated water models. A third research thrust involves mapping out the potential energy surfaces of small, conformationally flexible biomolecules, both isolated and solvated with one or more water molecules. The goals of this research are to characterize for selected systems all low-energy pathways at a sufficiently high level of theory to unambiguously establish the pathways accessed experimentally, and to provide data for testing and refining the polarizable force fields for subsequent use in characterizing more complex biomolecules. In terms of broader impacts, the PI has a strong track record of engaging undergraduates in research and in introducing undergraduate and graduate students to the field of computational science, including directing summer research programs for undergraduates for four years and establishing the University of Pittsburgh's Center for Molecular and Materials simulations.
