The H + CO ⇌ HCO reaction studied by ab initio benchmark calculations.

Abstract : : The title reaction has been calculated using complete active space self-consistent field and internally contracted multi-reference configuration interaction, including Davidson correction, calculations. Dunning's correlation consistent atomic basis sets, together with several complete basis set extrapolation schemes, were employed. Core-valence and scalar relativistic effects were also taken into account, as well as anharmonicity of the vibrational modes. Core-valence correlation appears to have a large impact on the calculated frequencies, spectroscopic constants, and on the energetics. In particular, the best estimate for the HCO (DCO) formation barrier height at 0 K, 4.54 ± 0.14 (4.43 ± 0.14) kcal mol(-1) is larger than previous theoretical works and well above the usually accepted value of 2.0 ± 0.4 kcal mol(-1), measured at room temperature. Inclusion of temperature and entropy at 298 K does not seem to be able to solve this discrepancy. The present theoretical barrier height is therefore the recommended value. The exo-ergicity of the HCO (DCO) dissociation reaction, predicted to be -13.36 ± 0.57 (-14.72 ± 0.57) kcal mol(-1), is slightly below the experimental value. Finally, all tested density functionals fail to reproduce accurately both the formation and dissociation barriers.
Type de document :
Article dans une revue
Journal of Chemical Physics, American Institute of Physics, 2013, 139 (16), pp.164310. 〈10.1063/1.4826171〉
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Contributeur : Denis Duflot <>
Soumis le : mercredi 6 novembre 2013 - 16:29:05
Dernière modification le : lundi 24 septembre 2018 - 16:04:03

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Phillip S Peters, Denis Duflot, Laurent Wiesenfeld, Céline Toubin. The H + CO ⇌ HCO reaction studied by ab initio benchmark calculations.. Journal of Chemical Physics, American Institute of Physics, 2013, 139 (16), pp.164310. 〈10.1063/1.4826171〉. 〈hal-00880708〉

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