| Texto completo | |
| Autor(es): |
Vichietti, R. M.
;
Spada, R. F. K.
;
da Silva, A. B. F.
;
Machado, F. B. C.
;
Haiduke, R. L. A.
Número total de Autores: 5
|
| Tipo de documento: | Artigo Científico |
| Fonte: | ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES; v. 225, n. 1 JUL 2016. |
| Citações Web of Science: | 2 |
| Resumo | |
A theoretical thermochemical and kinetic investigation of the thermal H-2 + CO <-> H2CO reaction was performed for a temperature range from 200 to 4000 K. Geometries and vibrational frequencies of reactants, product, and transition state (TS) were obtained at CCSD/cc-pVxZ (x = T and Q) levels and scaling factors were employed to consider anharmonicity effects on vibrational frequencies, zero-point energies, and thermal corrections provided by these methodologies. Enthalpies Gibbs energies, and rate constants for this reaction were determined by including a complete basis set extrapolation correction for the electronic properties calculated at CCSD(T)/cc-pVyZ (y = Q and 5) levels. Our study indicates that enthalpy changes for this reaction are highly dependent on temperature. Moreover, forward and reverse (high-pressure limit) rate constants were obtained from variational TS theory with quantum tunneling corrections. Thus, modified Arrhenius' equations were fitted by means of the best forward and reverse rate constant values, which provide very reliable estimates for these quantities within the temperature range between 700 and 4000 K. To our knowledge, this is the first kinetic study done for the forward H-2 + CO -> H2CO process in a wide temperature range. Finally, these results can be used to explain the formaldehyde abundance in hot and dense interstellar media, possibly providing data about the physical conditions associated with H2CO masers close to massive star-forming regions. (AU) | |
| Processo FAPESP: | 14/25734-0 - Estudo multiconfiguracional de reações elementares de diaminas (n2hx, x=1-4) com os átomos de hidrogênio, oxigênio e nitrogênio |
| Beneficiário: | Rene Felipe Keidel Spada |
| Modalidade de apoio: | Bolsas no Brasil - Pós-Doutorado |
| Processo FAPESP: | 14/24155-6 - Estudo de estados eletrônicos em hidrocarbonetos aromáticos policíclicos e suas propriedades eletrônicas como modelos de estruturas de grafeno |
| Beneficiário: | Francisco Bolivar Correto Machado |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |
| Processo FAPESP: | 10/18743-1 - Uso de multipolos da teoria quântica de átomos em moléculas e estudos cinéticos em sistemas encontrados no meio interestelar |
| Beneficiário: | Roberto Luiz Andrade Haiduke |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |
| Processo FAPESP: | 14/23714-1 - Cálculos relativísticos de estrutura eletrônica para avaliação de novos conjuntos de funções de base sem prolapso variacional |
| Beneficiário: | Roberto Luiz Andrade Haiduke |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |