In:
The Journal of Chemical Physics, AIP Publishing, Vol. 131, No. 11 ( 2009-09-21)
Abstract:
We present the Born–Oppenheimer coupled-channel dynamics of the reaction C12(D1)+H12(X Σ1g+)→CH(X Π2)+H(S2), considering the uncoupled CH2 states ã A11 and b̃ B11, the permutation-inversion symmetry, and Coriolis interactions. Using accurate MRCI potential energy surfaces (PESs), we obtain initial-state-resolved reaction probabilities, cross sections, and rate constants through the time-dependent, real wavepacket (WP) and flux methods, taking into account the proton-spin statistics for both electronic species. Comparing results on both PESs, we point out the role of the b̃ B11 upper state on the initial-state-resolved dynamics and on the thermal kinetic rate. WP probabilities at J=0 and cross sections at Ecol=0.080 eV agree quite well with quantum-mechanical time-independent findings. Probabilities and WP snapshots show the different reaction mechanisms on the PESs, i.e., an ã A11 indirect perpendicular insertion and a b̃ B11 direct sideways collision, associated with many and few sharp resonances, respectively. All cross sections are very large at low Ecol, decrease at high energies, and that of the lowest reactant state presents some weak resonances. As the temperature increases from 100 to 400 K, the ã A11 rate constant increases slightly from 1.37×10−10 to 1.43×10−10 cm3 s−1, whereas the b̃ B11 one decreases from 1.30×10−10 to 0.98×10−10 cm3 s−1. In this temperature range, the b̃ B11 contribution to the total rate constant thus decreases from 49% to 41%. At 300 K, the WP and experimental rates are equal to (2.45±0.08)×10−10 and (2.0±0.6)×10−10 cm3 s−1, respectively.
Type of Medium:
Online Resource
ISSN:
0021-9606
,
1089-7690
Language:
English
Publisher:
AIP Publishing
Publication Date:
2009
detail.hit.zdb_id:
3113-6
detail.hit.zdb_id:
1473050-9
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