Theoretical study of the dynamics and kinetics of the O + CS → CO + S chemical laser reaction, where CO shows a very high vibrational excitation

The dynamics and kinetics of the O(3P) + CS(X1sigma+) → CO(X1sigma+) + S(3P) chemical laser reaction was studied theoretically in detail for the first time, as a function of collision energy (0.0388-2.0 eV) and rovibrational excitation of CS. This was made using the quasi-classical trajectory (QCT)...

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Detalhes bibliográficos
Autores: Gamallo Belmonte, Pablo, Francia, Rafael, Martínez Ruiz, Rodrigo, Sayós Ortega, Ramón, González Pérez, Miguel
Tipo de documento: artigo
Estado:Versión aceptada para publicación
Data de publicação:2012
País:España
Recursos:Universidad de Barcelona
Repositório:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/163617
Acesso em linha:https://hdl.handle.net/2445/163617
Access Level:Acceso aberto
Palavra-chave:Cinètica química
Reaccions químiques
Col·lisions (Física)
Química quàntica
Chemical kinetics
Chemical reactions
Collisions (Physics)
Quantum chemistry
Descrição
Resumo:The dynamics and kinetics of the O(3P) + CS(X1sigma+) → CO(X1sigma+) + S(3P) chemical laser reaction was studied theoretically in detail for the first time, as a function of collision energy (0.0388-2.0 eV) and rovibrational excitation of CS. This was made using the quasi-classical trajectory (QCT) method and employing the best ab initio analytical ground potential energy surface (1 3A' PES) available. A broad set of properties was determined, including scalar and vector properties, and the reaction mode. The behaviors observed and the considerable formation of OCS collision complexes were interpreted from some characteristics of the PES (early barrier, shallow minimum in the exit channel, and high exoergicity (mainly channeled into CO vibration; up to ≈81% of the available energy) and the kinematics. The QCT vibrational and rotational CO populations and the vector properties show a quite good agreement with experiments, but the QCT rate constants disagree. To better account for the kinetics, we performed CASPT2/aug-cc-pVTZ ab initio calculations on the stationary points along the minimum energy path of the ground and first excited (1 3A'') PESs. The transition state theory, which can be satisfactorily applied here, leads to rate constants (100-2000 K) that are quite close to the measured ones, where comparison is possible (150-300 K). We expect that these results will encourage further theoretical and experimental developments.