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Non-Born-Oppenheimer Molecular Dynamics of the Spin-forbidden Reaction O(3P) + CO(X1Σ+) → CO2(X1Σg+)
Journal of Chemical Physics
  • Ahern W. Jasper
  • Richard Dawes, Missouri University of Science and Technology
Abstract

The lowest-energy singlet (1 1A') and two lowest-energy triplet (1 3A' and 1 3A') electronic states of CO2 are characterized using dynamically weighted multireference configuration interaction (dw-MRCI+Q) electronic structure theory calculations extrapolated to the complete basis set (CBS) limit. Global analytic representations of the dw-MRCI+Q/CBS singlet and triplet surfaces and of their CASSCF/aug-cc-pVQZ spin-orbit coupling surfaces are obtained via the interpolated moving least squares (IMLS) semiautomated surface fitting method. the spin-forbidden kinetics of the title reaction is calculated using the coupled IMLS surfaces and coherent switches with decay of mixing non-Born-Oppenheimer molecular dynamics. the calculated spin-forbidden association rate coefficient (corresponding to the high pressure limit of the rate coefficient) is 7-35 times larger at 1000-5000 K than the rate coefficient used in many detailed chemical models of combustion. a dynamical analysis of the multistate trajectories is presented. the trajectory calculations reveal direct (nonstatistical) and indirect (statistical) spin-forbidden reaction mechanisms and may be used to test the suitability of transition-state-theory-like statistical methods for spin-forbidden kinetics. Specifically, we consider the appropriateness of the "double passage" approximation, of assuming statistical distributions of seam crossings, and of applications of the unified statistical model for spin-forbidden reactions.

Department(s)
Chemistry
Keywords and Phrases
  • Analytic representation,
  • Complete basis set limit,
  • Electronic structure theory,
  • Interpolated moving least-squares,
  • Multi reference configuration interactions,
  • Statistical distribution,
  • Surface fitting method,
  • Trajectory calculations,
  • Carbon dioxide,
  • Electronic structure,
  • Molecular dynamics,
  • Reaction kinetics
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2013, American Institute of Physics (AIP), All rights reserved.
Publication Date
10-1-2013
Disciplines
Citation Information
Ahern W. Jasper and Richard Dawes. "Non-Born-Oppenheimer Molecular Dynamics of the Spin-forbidden Reaction O(3P) + CO(X1Σ+) → CO2(X1Σg+)" Journal of Chemical Physics Vol. 139 Iss. 15 (2013) ISSN: 0021-9606
Available at: http://works.bepress.com/richard_dawes/73/