Title

Near-threshold rotational excitation of molecular ions by electron impact

Authors

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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