Speaker: Bo Gao (University of Toledo)
In a conventional quantum theory of reactions , little can be known about a reaction without a detailed knowledge of the potential energy surface (PES), the accuracy of which is often insufficient for quantitative predications. This difficulty, coupled with the exponential growth of the Hilbert space beyond two-body, has limited the conventional theory to a few simple systems such as H+HD, with little hope for more complex systems.
The multichannel quantum-defect theory for reactions (MQDTR) offers a substantially different perspective. It asserts that much can be known about a quantum system simply from the types of long-range interactions among its constituents. Whatever not yet known can be characterized by a few energy-insensitive parameters, which can be further determined from a few experimental measurements without any knowledge of the short-range interaction, or even the strength of the long-range interaction. Such a paradigm frees the theory from being held hostage by the details of PES, while ready to take advantage of it when it is available. I will present some initial results of the theory including universal models for exoergic neutral-neutral and charge-neutral reactions, and will explain the origin of such universalities.
 Hu and Schatz, JCP 125, 132301 (2006).
 Gao, PRL 105, 263203 (2010).