Rates of the reaction C2H3+H-2 -> C2H4+H
The reaction C2H3 + H2 → C 2H4 + H has been studied by different direct ab initio approaches. Accurate rate constants in the temperature range 200-1200 K have been derived by time-independent scattering theory, employing R-matrix propagation on a 2D reduced dimensional G3B3 potential energy surface....
| Main Authors: | , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
2006
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| Summary: | The reaction C2H3 + H2 → C 2H4 + H has been studied by different direct ab initio approaches. Accurate rate constants in the temperature range 200-1200 K have been derived by time-independent scattering theory, employing R-matrix propagation on a 2D reduced dimensional G3B3 potential energy surface. Reported experimental reaction rates at room temperature vary over 3 orders of magnitude as they have to be determined indirectly. The computed room temperature rate of 2.1 × 10-18 cm3 molecule-1 s-1 in this study should remove this ambiguity. At higher temperatures the calculated rates meet experimental rates from direct measurements very well. The use of a reduced dimensionality model is justified by comparing full-dimensional semiclassical tunnelling contributions to those derived on a 2D potential with the same method. The employed semiclassical approach (small curvature tunnelling) yields very similar rates to the scattering approach, thus showing that small curvature tunnelling is a very reliable method to describe reactions like these. |
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