2025 Nick Besley Award: Justin Talbot

This special webinar event was presented by Justin Talbot, the recipient of the 2025 Nick Besley Award. Abstract: Elucidating the important role that nonadiabatic transitions play in renewable energy catalysis, biological systems, and atmospheric chemistry is a current challenge for computational chemistry. Key difficulties include building a sufficiently accurate representation of the excited-state potential energy surfaces and their couplings. To address these challenges, Justin Talbot and collaborators have incorporated an ab initio treatment of electronic structure theory—including the analytical evaluation of non-adiabatic couplings—with the symmetric quasi-classical Meyer-Miller model, which treats electronic and nuclear motions on an equal footing using classical mechanics. In this talk, he will discuss the benefits and pitfalls of such an approach and illustrate, using small gas-phase molecules as examples, how it might be employed to understand and predict the complex dynamics relevant to solar energy catalysis, photoinduced isomerization, and energy flow within molecules. Additionally, he will discuss how some predicted minimum energy excited state configurations can be unphysical—existing only within the construct of the Born-Oppenheimer approximation. Using ab initio calculations and Landau-Zener dynamics, he will present some examples of these “fantastical” minimum energy configurations, show how they correspond to unphysically high harmonic frequencies, and demonstrate how they collapse within femtoseconds to lower-energy electronic states. About the Presenter: Prof. Talbot earned his BS in physics and applied mathematics and his PhD in physical chemistry at the University of Utah, where he worked with Prof. Ryan Steele in applications and methods development for vibrational structure theory. He then did a postdoc at UC Berkeley, where he worked with Prof. Martin Head-Gordon, Dr. Stephen Cotton, and Prof. Bill Miller to study electronic structure and nonadiabatic molecular dynamics. He is now an assistant professor at Clemson University, where he leads a research group focused on ab initio electronic structure methods and molecular dynamics simulations, with applications in solar and green energy. He has also made significant contributions to Q-Chem specifically, including development of novel methods for computational vibrational spectroscopy and nonadiabatic dynamics. About the Award: The Nick Besley Award was established to recognize excellence in the development or application of new methods for computational spectroscopy in the Q-Chem open-teamware community project. It commemorates the contributions of Prof. Nick Besley, who is remembered for his multi-faceted contributions to electronic excited-state theory and methodology, with particular application to the prediction and rationalization of X-ray spectra.