On the Mechanism and Quantum Tunneling of the CO2 + OH Anion Reaction in Ice: A Computational Study

Jayaweera, Avon P. (författare)

Senevirathne, Bethmini, 1982 (författare): Gothenburg University,Göteborgs universitet,Institutionen för kemi och molekylärbiologi,Department of Chemistry and Molecular Biology

Weerasinghe, Samantha (författare)

Watanabe, Naoki (författare)

Nyman, Gunnar, 1957 (författare): Gothenburg University,Göteborgs universitet,Institutionen för kemi och molekylärbiologi,Department of Chemistry and Molecular Biology

Dulieu, Francois (författare)

Sameera, W. M. C. (författare)

(creator_code:org_t)

Relaterad länk:: https://gup.ub.gu.se...; visa fler...; https://doi.org/10.1...; visa färre...

Abstract Ämnesord

Stäng

The mechanism of the reaction between CO2 and OH- (anion) in ice cluster models was determined using density functional theory (DFT), employing the omega B97X-D functional and def2-TZVP basis sets for all atoms. A range of reaction barriers, 0.08-0.43 eV, were found, and the lowest energy path has a barrier of 0.08 eV, giving rise to the bicarbonate ion (HCO3-). Computed rate constants, accounting for quantum tunneling by employing the Eckart potential, suggest that the CO2 + OH- -> HCO3- reaction can operate in ice at low temperatures (e.g., 10 K). In contrast, relatively high reaction barriers (0.52-0.74 eV) were found for the CO2 + OH center dot (radical) -> HCO3 center dot (radical) reaction, and the computed rate constants at low temperatures (e.g., 10 K) are extremely small. Based on the computed data, we argue that OH- can react with CO2 trapped in interstellar ice at 10 K, and the product of the reaction, HCO3-, is stable in ice. On the other hand, the OH radical does not react with CO2 in ice. Therefore, we propose that OH anions in interstellar ice play a role in the formation of precursors of complex organic molecules (COMs) in the interstellar medium. The present findings will open a new dimension to explore the chemical evolution in the interstellar medium through the chemistry of anions in interstellar ices.

Av författaren/redakt...: Jayaweera, Avon ...; Senevirathne, Be ...; Weerasinghe, Sam ...; Watanabe, Naoki; Nyman, Gunnar, 1 ...; Dulieu, Francois; visa fler...; Sameera, W. M. C ...; visa färre...

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