CAREER: Self-consistent models of electronic dynamics and relaxation

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John Parkhill of The University of Notre Dame is supported by an award from the Chemical Theory, Models and Computational Methods program and the Macromolecular, Supramolecular and Nanochemistry program in the Chemistry Division to develop theories and computer software to model the motion of electrons in molecules that are stimulated by light. This software allows users to predict important photodynamic properties of materials. For example it could be used to improve photovoltaic materials, pigments, optical media, organic light emitting diodes, and other light emitting/absorbing materials without expensive synthetic trial-and-error. Improved mathematical models for how light imparts motion on clouds of electrons, and how these electrons lose their energy to vibrations of atomic nuclei and other surrounding material underlie these developments. John Parkhill and his research group also develop an open source chemistry web portal where the chemical community and educators can access and apply these tools without expensive computer hardware, software or expertise. The Parkhill group pursues self-consistent methods for studying non-equilibrium quantum electronic dynamics using dynamical embeddings that provide a common framework to treat extended systems, correlation, and vibronic effects. These tools fluidly expand the standard toolbox of molecular quantum mechanics into a regime where electronic states are statistically mixed. A self-consistent beyond mean-field correlated dynamics method is being developed to study the interplay between electron correlation and decoherence. The Parkhill group?s realtime transient absorption technique is being generalized to reproduce coherent multidimensional experiments. These new tools are used to produce real-time simulations of photo-induced charge separation that feature an accurate treatment of quantum correlation effects, thermalization, and the environmental surroundings of a molecule. These simulations shed light on the mechanisms controlling plasmonic generation of hot electrons and charge separation in photovolatics. Embedded dynamics methodology complements existing approaches by providing a unified and systematically improvable platform for studying electronic dynamics in condensed systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.