In this proposal funded by the Experimental Physical Chemistry Program of the Chemistry Division, Henning Meyer of the University of Georgia will pursue a program of research on the spectroscopy, predissociation, and scattering of van der Waals systems. IR and molecular beam scattering are used to study the electronic ground state and predissociation dynamics. Van der Waals systems involving different sources of internal angular momentum, electronic (NO) and internal rotational (acetaldehyde), will be complexed with molecules such as water, CO, nitrogen, methane, and HF. The influence of the internal angular momentum on the bound level structure of the complexes will be studied, as will the energy transfer efficiency of the complexes in bimolecular collisions. Resonance enhanced multiphoton ionization (REMPI) and ion time of flight analysis will be used to analyze fragmentation. The data will be analyzed with a view to establishing the effects of the internal angular momentum on the intermolecular dynamics, for example, with respect to non-adiabatic effects in rotational-electronic coupling and to large amplitude vibrations. The experimental studies will be complemented by a rigorous theoretical treatment, either based on first principles or within the framework of reasonable approximations.
The data gathered in this study will provide new insights relevant to intermolecular energy transfer and elementary reaction dynamics. In particular, the studies on acetaldehyde, an important air pollutant resulting from the oxidation of tropospheric hydrocarbons, adds to the understanding of the formation of tropospheric ozone. This fundamental project thus is important for understanding more practical environmental issues such as global change.