| Texto completo | |
| Autor(es): |
Kano, Filipe Gustavo
;
de Carvalho, Edson Firmino Viana
;
Ferrao, Luiz Fernando Araujo
;
Machado, Francisco Bolivar Correto
;
Roberto-Neto, Orlando
Número total de Autores: 5
|
| Tipo de documento: | Artigo Científico |
| Fonte: | Journal of Molecular Modeling; v. 30, n. 5, p. 11-pg., 2024-05-01. |
| Resumo | |
Context: One of the more significant sub-mechanisms of H-2/O-2 combustion involves the reaction of hydrogen peroxide with hydrogen atoms (H + H2O2), resulting in the production of OH + H2O (R1) and H-2 + HO2 (R2) paths. Previous experimental and ab initio calculations reveal some variations in the barrier height for (R1). To improve the energetics of both (R1) and (R2), single reference and multireference ab initio methods are employed, and the rate constants and H/D kinetic isotope effects (KIEs) are calculated as a function of temperature. For (R1), the best results for the barrier height and reaction energies computed with the CASPT2(15,11)/aug-cc-pV6Z are 5.2 and - 70.3 kcal.mol(-1), respectively. CCSD(T)/aug-cc-pV5Z + CV (core-valence) calculations for (R2) give 9.7 and - 15.6 kcal.mol(-1) to those parameters. The CVT/SCT rate constants of both paths agree well with the fitted rate constants from uncertainty-weighted statistical analysis of the 14-mechanism of H-2/O-2. The kinetic isotopic effect (k(H)/k(D)) for the reaction D + H2O2 -> DH + HO2 was found to be 0.47, which is in excellent agreement with the experimental value of 0.43. Methods: The structures of reactants, transition state, and products of (R1) and (R2) are calculated with the aug-cc-pVTZ basis set and M062X DFT, CCSD(T), and CASSCF methods. The barrier heights and reaction energies of (R1) and (R2) are computed using the M06-2X, CCSD(T), MRCI, and CASPT2 methods and various basis sets. The rate constants are calculated with the variational transition state theory including multidimensional tunneling corrections (VTST-MT), with potential energy surfaces built by the M06-2X/aug-cc-pVTZ approach. (AU) | |
| Processo FAPESP: | 22/16385-8 - Dispositivos orgânicos emissores de luz, conversores de energia via fissão singleto e materiais híbridos 0D/0D para produção de hidrogênio: abordagem da química computacional |
| Beneficiário: | Francisco Bolivar Correto Machado |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |
| Processo FAPESP: | 19/03729-8 - Desenvolvimento teórico-experimental de materiais energéticos aplicados à propulsão química |
| Beneficiário: | Luiz Fernando de Araújo Ferrão |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |