Authors

S. F. dos Santos; N. Douguet; V. Kokoouline;A. E. Orel

Comments

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Abbreviated Journal Title

J. Chem. Phys.

Keywords

QUANTUM-DEFECT THEORY; DOUBLE-RESONANCE SPECTROSCOPY; HIGH RYDBERG; STATES; ELECTRON-ION RECOMBINATION; VIBRATIONAL AUTOIONIZATION; TEMPERATURE-DEPENDENCE; AB-INITIO; IONIZATION; COEFFICIENTS; EXCITATION; Physics, Atomic, Molecular & Chemical

Abstract

We present a theoretical study of the indirect dissociative recombination of linear polyatomic ions at low collisional energies. The approach is based on the computation of the scattering matrix just above the ionization threshold and enables the explicit determination of all diabatic electronic couplings responsible for dissociative recombination. In addition, we use the multi-channel quantum-defect theory to demonstrate the precision of the scattering matrix by reproducing accurately ab initio Rydberg state energies of the neutral molecule. We consider the molecular ions N2H+ and HCO+ as benchmark systems of astrophysical interest and improve former theoretical studies, which had repeatedly produced smaller cross sections than experimentally measured. Specifically, we demonstrate the crucial role of the previously overlooked stretching modes for linear polyatomic ions with large permanent dipole moment. The theoretical cross sections for both ions agree well with experimental data over a wide energy range. Finally, we consider the potential role of the HOC+ isomer in the experimental cross sections of HCO+ at energies below 10 meV.

Journal Title

Journal of Chemical Physics

Volume

140

Issue/Number

16

Publication Date

1-1-2014

Document Type

Article

Language

English

First Page

12

WOS Identifier

WOS:000336047700032

ISSN

0021-9606

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