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Title: Cross sections of the O{sup +}+H{sub 2}{yields}OH{sup +}+H ion-molecule reaction and isotopic variants (D{sub 2}, HD): Quasiclassical trajectory study and comparison with experiments

A dynamics study [cross section and microscopic mechanism versus collision energy (E{sub T})] of the reaction O{sup +}+H{sub 2}{yields}OH{sup +}+H, which plays an important role in Earth's ionosphere and interstellar chemistry, was conducted using the quasiclassical trajectory method, employing an analytical potential energy surface (PES) recently derived by our group [R. Martinez et al., J. Chem. Phys. 120, 4705 (2004)]. Experimental excitation functions for the title reaction, as well as its isotopic variants with D{sub 2} and HD, were near-quantitatively reproduced in the calculations in the very broad collision energy range explored (E{sub T}=0.01-6.0 eV). Intramolecular and intermolecular isotopic effects were also examined, yielding data in good agreement with experimental results. The reaction occurs via two microscopic mechanisms (direct and nondirect abstraction). The results were satisfactorily interpreted based on the reaction probability and the maximum impact parameter dependences with E{sub T}, and considering the influence of the collinear [OHH]{sup +} absolute minimum of the PES on the evolution from reactants to products. The agreement between theory and experiment suggests that the reaction mainly occurs through the lowest energy PES and nonadiabatic processes are not very important in the wide collision energy range analyzed. Hence, the PES used to describe thismore » reaction is suitable for both kinetics and dynamics studies.« less
Authors:
; ;  [1] ;  [2]
  1. Departamento de Quimica, Universidad de La Rioja, C/Madre de Dios, 51, 26006 Logrono (Spain)
  2. (Spain)
Publication Date:
OSTI Identifier:
20723193
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 123; Journal Issue: 17; Other Information: DOI: 10.1063/1.2098667; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CATIONS; EV RANGE 01-10; EXCITATION FUNCTIONS; HYDROGEN IONS; IMPACT PARAMETER; ION-MOLECULE COLLISIONS; ISOTOPE EFFECTS; MILLI EV RANGE; OXYGEN; OXYGEN IONS; REACTION KINETICS; SURFACES; TRAJECTORIES