Non-Adiabatic Dynamics of B + H$_{2}$

ORAL

Abstract

A description of the non-adiabatic molecular dynamics of B + H$_{2}$ requires knowledge of the derivative coupling terms usually ignored in the standard Born-Oppenheimer approximation. These coupling terms are functions of the nuclear degrees of freedom, and for three body dynamics calculations, Jacobi coordinates are often employed because they separate the asymptotic Hamiltonian. On the other hand, code we use to compute derivative coupling terms produces output in Cartesian coordinates. The derivative coupling terms must therefore be transformed to Jacobi coordinates using the Jacobian matrix of the Jacobi to Cartesian transformation equations. This procedure is somewhat complicated by an ambiguity in the choice of the overall rotation coordinate in the plane containing the B and H$_{2}$ nuclei. This ambiguity is exacerbated by the fact that many choices of overall rotation angle will yield the same derivative coupling term with respect to the overall rotation coordinate, while at the same time producing disparate results for the derivative coupling term with respect to the Jacobi angle between the H$_{2}$ bond and the line between the B atom and H$_{2}$ center of mass. We discuss this ambiguity and its resolution using a collinear two body problem, and apply the resolution to the B + H$_{2}$ system to obtain derivative coupling terms and associated diabatic surfaces suitable for dynamics calculations.

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Authors

  • David Weeks

  • Perry Yaney

    Department of Physics, University of Oregon, USAF Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson AFB, Ohio, NHMFL, CRIEPI, UCSD, University of Dayton, L-3 Communications Cincinnati Electronics, University of Georgia, Air Force Research Laboratory, Anteon Corporation, California State University-Chico, The Ohio State University, Univ. Akron, Air Force Institute of Technology, Albion College, Albion, MI 49224, Physics Department, University of Florida, Gainesville, Mound Laser \& Photonics Center, Inc., Hitachi Global Storage Technologies, San Jose, CA 95120, University of Dayton Research Institute, University of South Alabama, Jet Propulsion Laboratory, Anteon, Universidad Michoacana de San Nicolas de Hidalgo, Morelia, Michoac\'{a}n, Mexico, Department of Chemistry, The University of Akron, Department of Physics, The University of Akron, Physics Department and The Future-Chips Constellation, Renssalaer Polytechnic Institute, Local Co-Chair