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 threedimensional 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. As a result, 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:

Mauguière, Frédéric A. L. ^[1]; Collins, Peter ^[1]; Stamatiadis, Stamatis ^[2]; Li, Anyang ^[3]; Ezra, Gregory S. ^[4]; Farantos, Stavros C. ^[5]; Kramer, Zeb C. ^[4]; Carpenter, Barry K. ^[6]; Wiggins, Stephen ^[1]; Guo, Hua ^[3]

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+ Show Author Affiliations

1. School of Mathematics, University of Bristol, Bristol BS8 1TW, United Kingdom
2. Department of Materials Science and Technology, University of Crete, Iraklion 710 03, Greece
3. Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
4. Baker Laboratory, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
5. Institute of Electronic Structure and Laser, Foundation for Research and Technology—Hellas, and Department of Chemistry, University of Crete, Iraklion 711 10, Greece
6. School of Chemistry, Cardiff University, Cardiff CF10 3AT, United Kingdom

Publication Date:

Fri Mar 11 00:00:00 EST 2016

Research Org.:

Univ. of New Mexico, Albuquerque, NM (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1241435

Alternate Identifier(s):

OSTI ID: 1267205

Grant/Contract Number:  

DF-FG02-05ER15694; FG02-05ER15694

Resource Type:

Published Article

Journal Name:

Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory

Additional Journal Information:

Journal Name: Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory Journal Volume: 120 Journal Issue: 27; Journal ID: ISSN 1089-5639

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY