Experiments, Small Molecules, Unpaired Electrons

Abstract

In this session there was representation from three different groups making contributions to our understanding of Van der Waals interactions in open shell systems. First, Benoit Soep discussed metal atom bimolecular cluster spectroscopy in Hg and Ca atom studies. The clusters are probed via LIF excitation of the complex using the bare metal atom electronic transition as the chromophore. Intermolecular energy transfer or chemical reaction in the complexes is then probed by total fluorescence and/or state resolved detection of products. The intermolecular potentials for these open shell systems, particularly between open shell atom+atom.and atom+diatom systems, can be directly probed by crossed beam scattering methods. Results from this experimental approach were presented by Piergorgio Cassevechia for a number of systems such as open shell halogen atoms, O(³P), and NO. A third perspective on recent developments in this field was provided by Marsha Lester with work in her group on complexes of OH radical with Ar atoms. These studies elucidate the dynamics of vibrational predissociation in the weakly bound, Ar + ²Π OH, ground and the relatively strongly bound, Ar + ²Σ OH, electronically excited state observed via laser induced florescence. A full description of these talks is provided in the following chapters. However, in the interest of providing as complete as possible an overview of the field, a short summary of the questions and answers that arose during the discussion periods between the talks is reproduced below.