Does the Cl + CH4 -> H + CH3Cl Reaction Proceed via Walden Inversion?
We report a chemically accurate global ab initio full-dimensional potential energy surface (PES) for the Cl(P-2(3/2)) + CH4 reaction improving the high-energy region of our previous PES [Czako, G.; Bowman, J. M. Science 2011, 334, 343-346]. Besides the abstraction (HCl + CH3) and the Walden-inversio...
Elmentve itt :
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| Dokumentumtípus: | Cikk |
| Megjelent: |
2017
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| Sorozat: | JOURNAL OF PHYSICAL CHEMISTRY A
121 No. 49 |
| doi: | 10.1021/acs.jpca.7b10226 |
| mtmt: | 3313323 |
| Online Access: | http://publicatio.bibl.u-szeged.hu/17919 |
| Tartalmi kivonat: | We report a chemically accurate global ab initio full-dimensional potential energy surface (PES) for the Cl(P-2(3/2)) + CH4 reaction improving the high-energy region of our previous PES [Czako, 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 similar to 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 similar to 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. |
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| Terjedelem/Fizikai jellemzők: | 9415-9420 |
| ISSN: | 1089-5639 |