Speaker: Prof. Elizabeth McCormack, Bryn Mawr College

Title: Probing Long-Range Configurations of Molecular Hydrogen

Abstract: Very long-range molecular configurations are of interest in a variety of contexts, for example, in the astro-chemistry of cold molecular clouds and in planetary atmospheres, including our own. Such states can be more than 10 times the size of the ground state and often possess energies above multiple ionization potentials and dissociation limits resulting in diverse and complex decay dynamics. Many of these configurations possess a double-well character arising from the interaction of molecular Rydberg states, repulsive doubly-excited states, and ionic states. The ion pair in hydrogen, an unusual molecular configuration consisting of one proton shrouded in a cloud of two electrons separated very far from another proton, is notoriously difficult to create and study. We report results on our investigation of such states using resonantly enhanced multi-photon ionization via the state to probe the H(n=1) + H(n=3) dissociation threshold energy region.