Molecular Physics seminar

Dynamical Outcomes of Quenching: Reflections on a Conical Intersection

by Prof. Marsha I. Lester (University of Pennsylvania, USA)

FA32 ()


Hydroxyl radicals are important in combustion and atmospheric environments, where they are often detected by laser-induced fluorescence (LIF) on the A2Sigma+ - X 2Π band system. However, collision partners known to quench electronically excited OH A2Sigma+ radicals are ubiquitous in these environments. Thus, great effort has been made to quantify the rates and/or cross sections for collisional quenching, so that its effects on LIF signals may be taken into account to allow an accurate determination of OH concentrations. Despite extensive kinetic measurements, fundamental questions remain regarding the fate of the collisionally quenched molecules and the mechanism by which these nonadiabatic processes occur. This presentation will overview fundamental chemical dynamics studies aimed at understanding the quenching of OH A2Sigma+ by molecular partners (M = H2, O2, N2, CO, CO2, H2O). Some comparisons will be made with dissociative recombination of H3O+.