Improved Methods for Including Vibronic and Environmental Effects in Simulations of Optical Spectroscopy

University Of California - Merced, Merced CA

Investigators

Abstract

Professor Christine Isborn of the University of California Merced is supported by an award from the Chemical Theory, Models and Computational Methods program in the Division of Chemistry to develop and apply improved methods for simulating optical spectroscopy. Her research focuses on how the environment (e.g. solvent, surface, protein) surrounding a chromophore (light absorber) affects the electronic excited states. New simulation techniques will be developed that better represent atomistic and experimental details. The new methods for simulating optical spectroscopy in complex environments can be used to guide the design of new molecules and materials that have desired optical properties. Improved tools for simulating optical spectroscopy will improve understanding of electronic excitation processes in complex environments, with the potential for this increased understanding to drive new technologies in the fields of photovoltaics, electro-optics, or photo-catalysis. Professor Isborn also engages in broader impact activities at the high school, undergraduate, and graduate student levels. To serve a primarily first-generation student population, undergraduate students create short videos in both English and the student’s native language in which they discuss their experiences. A week-long graduate student level summer school focused on the fundamentals and applications of computer theory helps to train the next generation of chemists for the workforce of the future. Optical spectroscopy, including optical absorption, fluorescence, and time-resolved ultrafast electronic spectroscopy, is the most commonly used technique for probing the electronic behavior of many chemical systems and molecular reactions. These methods are sensitive to environmental effects, however, traditional approaches for modeling optical spectra of molecules in complex environments often fail to reproduce spectral shapes due to either lacking vibronic effects and/or missing specific interactions between the molecule and its environment. Professor Isborn and her group are developing a family of approaches for simulating optical absorption, fluorescence, and ultrafast spectra that account for both vibronic transitions and specific solute-solvent-environment interactions by computing ground and excited vibrational modes in the presence of the atomistic environment. They are examining how the environment affects spectral shapes and electronic relaxation for a variety of chromophores within complex environments. 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.