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Colloquium | Chemical Sciences and Engineering

New Insights into the NO3 Radical: The Molecule That Has Taken So Much Finally Gives

CSE Colloquium

Abstract: The ground electronic state of the NO3 radical represents one of the more highly studied cases of vibronic coupling in small molecules. It has been studied experimentally by infrared, dispersed fluorescence and negative ion photoelectron spectroscopy, while theoreticians have done extensive work, as well. While it is not completely accepted by the spectroscopic community, this electronic state is profoundly affected by vibronic coupling with the second excited electronic state, an effect that leads to no small number of curiosities associated with the ground state level structure and spectra. Very recently, this molecule has been targeted by an extension of the Slow-Electron velocity-map imaging (SEVI) method in which the photodetachment process takes place from an excited vibrational state of the anion. This work has led to the discovery of yet more curiosities in this system, here present in the vibrational level structure of the anion. Unlike the neutral ground state curiosities -- which have caused confusion and uncertainty for many researchers -- those in the anion act to facilitate understanding of this system. Together with simulations of photodetachment from various vibrationally excited states of the negative ion, the results unambiguously confirm a long- and hotly-debated reassignment of the ground state vibrational spectrum.

Bio: John F. Stanton received his B.G.S. (General Studies) degree from the University of Michigan in 1984 and his PhD in Chemical Physics from Harvard in 1988.    After postdoctoral stints at U. Chicago and U. Florida he moved to the University of Texas in midsummer 1993, where he remained for 24 years.   In 2017, he returned to the University of Florida, where he serves as the William R. Kenan Professor, and directs both the Physical Chemistry Division and the Quantum Theory Project.    He enjoys research in quantum chemistry and molecular spectroscopy, has developed a taste for thermochemistry, and is still learning kinetics.  In addition, he greatly enjoys teaching physical chemistry to undergraduate students.