Near-threshold rotational excitation of molecular ions by electron impact

    Authors

    A. Faure; V. Kokoouline; C. H. Greene;J. Tennyson

    Comments

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    Abbreviated Journal Title

    J. Phys. B-At. Mol. Opt. Phys.

    Keywords

    QUANTUM-DEFECT THEORY; SCATTERING; COLLISIONS; DYNAMICS; MATRIX; H-3(+); Optics; Physics, Atomic, Molecular & Chemical

    Abstract

    New cross sections for the rotational excitation of H-3(+) by electrons are calculated ab initio at low impact energies. The validity of the adiabatic-nuclei-rotation (ANR) approximation, combined with R-matrix wavefunctions, is assessed by comparison with rovibrational quantum defect theory calculations based on the treatment of Kokoouline and Greene (2003 Phys. Rev. A68 012703). Pure ANR excitation cross sections are shown to be accurate down to threshold, except in the presence of large oscillating Rydberg resonances. These resonances occur for transitions with Delta J = 1 and are caused by closed-channel effects. A simple analytic formula is derived for averaging the rotational probabilities over such resonances in a 3-channel problem. In accord with the Wigner law for an attractive Coulomb field, rotational excitation cross sections are shown to be large and finite at threshold, with a significant but moderate contribution from closed-channels.

    Journal Title

    Journal of Physics B-Atomic Molecular and Optical Physics

    Volume

    39

    Issue/Number

    20

    Publication Date

    1-1-2006

    Document Type

    Article

    Language

    English

    First Page

    4261

    Last Page

    4273

    WOS Identifier

    WOS:000242475700023

    ISSN

    0953-4075

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