skip to main content

Title: Electronic nonadiabatic effects in low temperature radical-radical reactions. I. C({sup 3}P) + OH({sup 2}Π)

The formation of collision complexes, as a first step towards reaction, in collisions between two open-electronic shell radicals is treated within an adiabatic channel approach. Adiabatic channel potentials are constructed on the basis of asymptotic electrostatic, induction, dispersion, and exchange interactions, accounting for spin-orbit coupling within the multitude of electronic states arising from the separated reactants. Suitable coupling schemes (such as rotational + electronic) are designed to secure maximum adiabaticity of the channels. The reaction between C({sup 3}P) and OH({sup 2}Π) is treated as a representative example. The results show that the low temperature association rate coefficients in general cannot be represented by results obtained with a single (generally the lowest) potential energy surface of the adduct, asymptotically reaching the lowest fine-structure states of the reactants, and a factor accounting for the thermal population of the latter states. Instead, the influence of non-Born–Oppenheimer couplings within the multitude of electronic states arising during the encounter markedly increases the capture rates. This effect extends up to temperatures of several hundred K.
Authors:
 [1] ;  [2] ;  [3] ;  [1] ;  [4]
  1. Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, Göttingen D-37077 (Germany)
  2. Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg 11, Göttingen D-37077 (Germany)
  3. (Israel)
  4. (Germany)
Publication Date:
OSTI Identifier:
22419932
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BORN-OPPENHEIMER APPROXIMATION; COLLISIONS; COUPLINGS; DISPERSIONS; FINE STRUCTURE; L-S COUPLING; RADICALS; SURFACES