Adjustment of Born-Oppenheimer electronic wave functions to simplify close coupling calculations

Authors

  • Robert J. Buenker,

    Corresponding author
    1. Fachbereich C-Mathematik und Naturwissenschaften, Bergische Universität Wuppertal, Gaussstr. 20, D-42119 Wuppertal, Germany
    • Fachbereich C-Mathematik und Naturwissenschaften, Bergische Universität Wuppertal, Gaussstr. 20, D-42119 Wuppertal, Germany
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  • Heinz-Peter Liebermann,

    1. Fachbereich C-Mathematik und Naturwissenschaften, Bergische Universität Wuppertal, Gaussstr. 20, D-42119 Wuppertal, Germany
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  • Yu Zhang,

    1. College of Material Sciences and Optoelectronic Technology, Graduate University of the Chinese Academy of Sciences, PO Box 4588, Beijing 100049, China
    2. Data Center for High Energy Density Physics, Institute of Applied Physics and Computational Mathematics, PO Box 8009, Beijing 100088, China
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  • Yong Wu,

    1. Data Center for High Energy Density Physics, Institute of Applied Physics and Computational Mathematics, PO Box 8009, Beijing 100088, China
    2. Department of Physics and Astronomy and the Center for Simulational Physics, University of Georgia, Athens, Georgia 30602-2451
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  • Lingling Yan,

    1. College of Material Sciences and Optoelectronic Technology, Graduate University of the Chinese Academy of Sciences, PO Box 4588, Beijing 100049, China
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  • Chunhua Liu,

    1. College of Material Sciences and Optoelectronic Technology, Graduate University of the Chinese Academy of Sciences, PO Box 4588, Beijing 100049, China
    2. Data Center for High Energy Density Physics, Institute of Applied Physics and Computational Mathematics, PO Box 8009, Beijing 100088, China
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  • Yizhi Qu,

    1. College of Material Sciences and Optoelectronic Technology, Graduate University of the Chinese Academy of Sciences, PO Box 4588, Beijing 100049, China
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  • Jianguo Wang

    1. Data Center for High Energy Density Physics, Institute of Applied Physics and Computational Mathematics, PO Box 8009, Beijing 100088, China
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Abstract

Technical problems connected with use of the Born-Oppenheimer clamped-nuclei approximation to generate electronic wave functions, potential energy surfaces (PES), and associated properties are discussed. A computational procedure for adjusting the phases of the wave functions, as well as their order when potential crossings occur, is presented which is based on the calculation of overlaps between sets of molecular orbitals and configuration interaction eigenfunctions obtained at neighboring nuclear conformations. This approach has significant advantages for theoretical treatments describing atomic collisions and photo-dissociation processes by means of ab initio PES, electronic transition moments, and nonadiabatic radial and rotational coupling matrix elements. It ensures that the electronic wave functions are continuous over the entire range of nuclear conformations considered, thereby greatly simplifying the process of obtaining the above quantities from the results of single-point Born-Oppenheimer calculations. The overlap results are also used to define a diabatic transformation of the wave functions obtained for conical intersections that greatly simplifies the computation of off-diagonal matrix elements by eliminating the need for complex phase factors. © 2013 Wiley Periodicals, Inc.

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