Born–Oppenheimer and Renner–Teller coupled-channel quantum reaction dynamics of O(3P) + H2+(X2Σg+) collisions
| Autor: | Miguel González, Carlo Petrongolo, Paolo Defazio, Pablo Gamallo, Miguel Paniagua |
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| Přispěvatelé: | UAM. Departamento de Química Física Aplicada |
| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | Biblos-e Archivo. Repositorio Institucional de la UAM instname |
| ISSN: | 1463-9084 1463-9076 2011-2785 |
| Popis: | We present Born-Oppenheimer (BO) and Renner-Teller (RT) time dependent quantum dynamics studies of the reactions O(3P) + H2+(X2Σg+) → OH+(X3Σ-) + H(2S) and OH(X2Π) + H+. We consider the OH2+ X˜2A″ and Ã2A′ electronic states that correlate with a linear 2Π species. The electronic angular momenta operators L and L2 are considered in nonadiabatic coupled-channel calculations, where the associated RT effects are due to diagonal VRT potentials that add up to the PESs and to off-diagonal CRTcouplings between the potential energy surfaces (PESs). Initial-state-resolved reaction probabilities PI, integral cross sections σI, and rate constants kI are obtained using recent ab initio PESs and couplings and the real wavepacket formalism. Because the PESs are strongly attractive, PI have no threshold energy and are large, σI decrease with collision energy, and kI depend little on the temperature. The X˜2A″ PES is up to three times more reactive than the Ã2A′ PES and H2+ rotational effects (j0 = 0, 1) are negligible. The diagonal VRT potentials are strongly repulsive at the collinearity and nearly halve all low-energy observables with respect to the BO ones. The off-diagonal CRTcouplings are important at low partial waves, where they mix the X˜2A″ and Ã2A′ states up to ∼20%. However, VRT effects predominate over the CRT ones that change at most by ∼19% the BO values of σI and kI. The reaction O(3P) + H2+(X2Σg+) → OH+(X3Σ-) + H(2S) is probably one of the most reactive atom + diatom collisions because its RT rate constant at room temperature is equal to 2.26 × 10-10 cm3 s-1. Within the BO approximation, the present results agree rather well with recent quasiclassical and centrifugal-sudden data using the sa me PESs This work was supported by the Spanish Ministry of Science and Innovation (MICINN projects CTQ2011-27857-C02-01 and CONSOLIDER INGENIO 2010 under grant no. CSD2009-00038 entitled ‘‘Molecular Astrophysics: the Herschel and Alma era’’). Thanks are also given to the ‘‘Generalitat de Catalunya’’ (Autonomous Government of Catalonia; refs. 2014SGR 25, 2014SGR 1582 and XRQTC) for some help. We gratefully acknowledge H. Guo and D. Xie for the matrix elements of the electronic angular momenta |
| Databáze: | OpenAIRE |
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