The Si + SO<SUB>2</SUB> collision and an extended network of neutral-neutral reactions between silicon and sulphur bearing species
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en
Article de revue
Este ítem está publicado en
Monthly Notices of the Royal Astronomical Society. 2022, vol. 515, p. 369-377
Oxford University Press (OUP): Policy P - Oxford Open Option A
Resumen en inglés
The Si + SO<SUB>2</SUB> reaction is investigated to verify its impact on the abundances of molecules with astrochemical interest, such as SiS, SiO, SO, and others. According to our results Si(<SUP>3</SUP>P) and SO<SUB>2</SUB> ...Leer más >
The Si + SO<SUB>2</SUB> reaction is investigated to verify its impact on the abundances of molecules with astrochemical interest, such as SiS, SiO, SO, and others. According to our results Si(<SUP>3</SUP>P) and SO<SUB>2</SUB> react barrierlessly yielding only the monoxides SO and SiO as products. No favourable pathway has been found leading to other products, and this reaction should not contribute to SiS abundance. Furthermore, it is predicted that SiS is stable in collisions with O<SUB>2</SUB>, and that S(<SUP>3</SUP>P) + SiO<SUB>2</SUB> and O(<SUP>3</SUP>P)+OSiS will also produce SO + SiO. Using these results and gathering further experimental and computational data from the literature, we provide an extended network of neutral-neutral reactions involving Si- and S-bearing molecules. The effects of these reactions were examined in a protostellar shock model, using the NAUTILUS gas-grain code. This consisted in simulating the physicochemical conditions of a shocked gas evolving from (i) primeval cold core, (ii) the shock region itself, (iii) and finally the gas bulk conditions after the passage of the shock. Emphasizing on the cloud ages and including systematically these chemical reactions, we found that [SiS/H<SUB>2</SUB>] can be of the order of ~10<SUP>-8</SUP> in shocks that evolves from clouds of t = 1 × 10<SUP>6</SUP> yr, whose values are mostly affected by the SiS + O $\longrightarrow$SiO + S reaction. Perspectives on further models along with observations are discussed in the context of sources harbouring molecular outflows.< Leer menos
Palabras clave en inglés
astrochemistry
molecular data
ISM: abundances
ISM: evolution
ISM: molecules
Astrophysics - Astrophysics of Galaxies
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