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Title: Scattering matrix approach to the dissociative recombination of HCO{sup +} and N{sub 2}H{sup +}

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 N{sub 2}H{sup +} and HCO{sup +} 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{sup +} isomer in the experimental cross sections of HCO{sup +} at energies below 10 meV.
Authors:
; ;  [1] ;  [2]
  1. Department of Chemical Engineering and Material Sciences, University of California, Davis, California 95616 (United States)
  2. Department of Physics, University of Central Florida, Florida 32816 (United States)
Publication Date:
OSTI Identifier:
22253021
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 140; Journal Issue: 16; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACCURACY; CALCULATION METHODS; CROSS SECTIONS; DIPOLE MOMENTS; ISOMERS; MEV RANGE; MOLECULAR IONS; QUANTUM MECHANICS; RECOMBINATION; RYDBERG STATES; SCATTERING