title: Toward Understanding the Roaming Mechanism in H + MgH → Mg + HH Reaction.
abstract: The roaming mechanism in the reaction H + MgH →Mg + HH is investigated by classical and quantum dynamics employing an accurate ab initio three-dimensional ground electronic state potential energy surface. The reaction dynamics are explored by running trajectories initialized on a four-dimensional dividing surface anchored on three-dimensional normally hyperbolic invariant manifold associated with a family of unstable orbiting periodic orbits in the entrance channel of the reaction (H + MgH). By locating periodic orbits localized in the HMgH well or involving H orbiting around the MgH diatom, and following their continuation with the total energy, regions in phase space where reactive or nonreactive trajectories may be trapped are found. In this way roaming reaction pathways are deduced in phase space. Patterns similar to periodic orbits projected into configuration space are found for the quantum bound and resonance eigenstates. Roaming is attributed to the capture of the trajectories in the neighborhood of certain periodic orbits. The complex forming trajectories in the HMgH well can either return to the radical channel or "roam" to the MgHH minimum from where the molecule may react.
authors.affiliation: School of Mathematics, University of Bristol , Bristol BS8 1TW, United Kingdom.
authors.forename: Frédéric A L
authors.initials: FA
authors.lastname: Mauguière
authors.affiliation: School of Mathematics, University of Bristol , Bristol BS8 1TW, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: Collins
authors.affiliation: Department of Materials Science and Technology, University of Crete , Iraklion 710 03, Greece.
authors.forename: Stamatis
authors.initials: S
authors.lastname: Stamatiadis
authors.affiliation: Department of Chemistry and Chemical Biology, University of New Mexico , Albuquerque, New Mexico 87131, United States.
authors.forename: Anyang
authors.initials: A
authors.lastname: Li
authors.affiliation: Baker Laboratory, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States.
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Ezra
authors.affiliation: Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, and Department of Chemistry, University of Crete, Iraklion 711 10, Greece.
authors.forename: Stavros C
authors.initials: SC
authors.lastname: Farantos
authors.affiliation: Baker Laboratory, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States.
authors.forename: Zeb C
authors.initials: ZC
authors.lastname: Kramer
authors.affiliation: School of Chemistry, Cardiff University , Cardiff CF10 3AT, United Kingdom.
authors.forename: Barry K
authors.initials: BK
authors.lastname: Carpenter
authors.affiliation: School of Mathematics, University of Bristol , Bristol BS8 1TW, United Kingdom.
authors.forename: Stephen
authors.initials: S
authors.lastname: Wiggins
authors.affiliation: Department of Chemistry and Chemical Biology, University of New Mexico , Albuquerque, New Mexico 87131, United States.
authors.forename: Hua
authors.initials: H
authors.lastname: Guo