Anne McCoy of The Ohio State University is supported by an award from the Chemical Theory, Models and Computational Methods program within the Division of Chemistry for the development of theoretical tools to unravel the spectroscopy and dynamics of molecular systems that undergo large amplitude motions. The work involves extensions of the Diffusion Monte Carlo (DMC) technique including the development of "on-the-fly" DMC and using DMC to evaluate measurable quantities including energies and intensities of ro-vibrational transitions. McCoy and her coworkers are using Diffusion Monte Carlo to develop potential energy and dipole moment surfaces. They also employ reduced dimensional approaches to explore photoinduced proton translocation and spectroscopic manifestations of hydrogen bonding more generally. The research focuses on systems of current interest to experimentalists as well as theorists, and the results will be used to extract physical insights from spectroscopic measurements.
By opening up a broad range of molecular and ionic systems for investigation, the work is having a broad impact on the study of systems of astrochemical and environmental importance in addition to deepening our understanding of hydrogen bonding and proton transfer in aqueous solution. The majority of students engaged in this research are from under-represented groups in the physical sciences.