title: Photoassociation Spectroscopy in Penning Ionization Reactions at Sub-Kelvin Temperatures.
abstract: Penning ionization reactions in merged beams with precisely controlled collision energies have been shown to accurately probe quantum mechanical effects in reactive collisions. A complete microscopic understanding of the reaction is, however, faced with two major challenges-the highly excited character of the reaction's entrance channel and the limited precision of even the best state-of-the-art ab initio potential energy surfaces. Here, we suggest photoassociation spectroscopy as a tool to identify the character of orbiting resonances in the entrance channel and probe the ionization width as a function of interparticle separation. We introduce the basic concept, using the example of metastable helium and argon, and discuss the general conditions under which this type of spectroscopy will be successful.
authors.affiliation: Theoretische Physik, Universität Kassel , Heinrich-Plett-Straße 40, 34132 Kassel, Germany.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Skomorowski
authors.affiliation: Department of Chemical Physics, Weizmann Institute of Science , Rehovot 76100, Israel.
authors.forename: Yuval
authors.initials: Y
authors.lastname: Shagam
authors.affiliation: Department of Chemical Physics, Weizmann Institute of Science , Rehovot 76100, Israel.
authors.forename: Edvardas
authors.initials: E
authors.lastname: Narevicius
authors.affiliation: Theoretische Physik, Universität Kassel , Heinrich-Plett-Straße 40, 34132 Kassel, Germany.
authors.forename: Christiane P
authors.initials: CP
authors.lastname: Koch