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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

THE H-2 + CO <-> H2CO REACTION: RATE CONSTANTS AND RELEVANCE TO HOT AND DENSE ASTROPHYSICAL MEDIA

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Author(s):
Vichietti, R. M. ; Spada, R. F. K. ; da Silva, A. B. F. ; Machado, F. B. C. ; Haiduke, R. L. A.
Total Authors: 5
Document type: Journal article
Source: ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES; v. 225, n. 1 JUL 2016.
Web of Science Citations: 2
Abstract

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)

FAPESP's process: 14/25734-0 - MULTI-CONFIGURATIONAL study of diamines (N2HX, X=1-4) reactions with the hydrogen, oxygen and nitrogen atoms
Grantee:Rene Felipe Keidel Spada
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 14/23714-1 - Electronic structure relativistic calculations for evaluation of new prolapse-free basis sets
Grantee:Roberto Luiz Andrade Haiduke
Support type: Regular Research Grants
FAPESP's process: 14/24155-6 - Study of electronic states in polycyclic aromatic hydrocarbons and their properties as models of electronic graphene structures
Grantee:Francisco Bolivar Correto Machado
Support type: Regular Research Grants
FAPESP's process: 10/18743-1 - Employment of multipoles from the quantum theory of atoms in molecules and kinetic studies in systems found in the interstellar medium
Grantee:Roberto Luiz Andrade Haiduke
Support type: Regular Research Grants