Does the Cl + CH4 → H + CH3Cl Reaction Proceed via Walden Inversion?

László Krotos, G. Czakó

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We report a chemically accurate global ab initio full-dimensional potential energy surface (PES) for the Cl(2P3/2) + CH4 reaction improving the high-energy region of our previous PES [Czakó, G.; Bowman, J. M. Science 2011, 334, 343-346]. Besides the abstraction (HCl + CH3) and the Walden-inversion substitution (H + CH3Cl) channels, the new PES accurately describes novel substitution pathways via retention of configuration. Quasiclassical trajectory simulation on this PES reveals that the substitution channel opens around 40 kcal/mol collision energy via Walden inversion and the retention cross sections raise from ∼50 kcal/mol. At collision energy of 80 kcal/mol, the retention pathways provide nearly 40% of the substitution cross section, and retention substitution may become the dominant mechanism of the Cl + CH4 reaction at superhigh collision energies. The substitution probability can be as high as ∼70% at zero impact parameter (b) and decreases rapidly with increasing b, whereas the abstraction opacity function is broad having 5-10% probability over a larger b-range. The high-energy angular distributions show scattering into forward and backward directions for the abstraction (direct stripping) and face-attack Walden-inversion substitution (direct rebound) channels, respectively. Retention can proceed via edge- and vertex-attack pathways producing dominant sideways scattering because the breaking C-H or Cl-H bond is usually at a side position of the forming Cl-C bond.

Original languageEnglish
Pages (from-to)9415-9420
Number of pages6
JournalJournal of Physical Chemistry A
Volume121
Issue number49
DOIs
Publication statusPublished - Dec 14 2017

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Substitution reactions
Potential energy surfaces
substitutes
inversions
potential energy
attack
collisions
energy
Forward scattering
Angular distribution
cross sections
Opacity
forward scattering
opacity
stripping
apexes
angular distribution
Trajectories
trajectories
Scattering

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

Does the Cl + CH4 → H + CH3Cl Reaction Proceed via Walden Inversion? / Krotos, László; Czakó, G.

In: Journal of Physical Chemistry A, Vol. 121, No. 49, 14.12.2017, p. 9415-9420.

Research output: Contribution to journalArticle

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