REACTIVE DESORPTION AND RADIATIVE ASSOCIATION AS POSSIBLE DRIVERS OF COMPLEX MOLECULE FORMATION IN THE COLD INTERSTELLAR MEDIUM

By A. Vasyunin, E. Herbst. 2013

182 citations recorded by the source corpus.

The recent discovery of terrestrial-type organic species such as methyl formate and dimethyl ether in the cold interstellar gas has proved that the formation of organic matter in the Galaxy begins at a much earlier stage of star formation than was previously thought. This discovery represents a challenge for astrochemical modelers. The abundances of these molecules cannot be explained by the previously developed “warm-up” scenario, in which organic molecules are formed via diffusive chemistry on surfaces of interstellar grains starting at 30 K, and then released to the gas at higher temperatures during later stages of star formation. In this article, we investigate an alternative scenario in which complex organic species are formed via a sequence of gas-phase reactions between precursor species formed on grain surfaces and then ejected into the gas via efficient reactive desorption, a process in which non-thermal desorption occurs as a result of conversion of the exothermicity of chemical reactions into the ejection of products from the surface. The proposed scenario leads to reasonable if somewhat mixed results at temperatures as low as 10 K and may be considered as a step toward the explanation of abundances of terrestrial-like organic species observed during the earliest stages of star formation.

Subfields: Astronomy and Astrophysics, Organic Chemistry, Physical and Theoretical Chemistry

View Paper: https://www.semanticscholar.org/paper/c2b26feb8c8a79861cb98a5dab6c8995adc51d7d

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In Astronomy and Astrophysics

1. E. Herbst
2. P. Caselli
3. Cecilia Ceccarelli
4. V. Wakelam
5. A. Vasyunin
6. R. Garrod
7. J. Loison
8. Y. Aikawa

In Organic Chemistry

1. P. Caselli
2. V. Wakelam
3. Cecilia Ceccarelli
4. I. Jiménez-Serra
5. Franccois Dulieu
6. J. Loison
7. R. Méreau
8. M. Ruaud

In Physical and Theoretical Chemistry

1. M. Ruaud
2. J. Loison
3. A. Vasyunin
4. V. Wakelam
5. Cecilia Ceccarelli
6. E. Herbst
7. P. Caselli
8. R. Méreau

Citations in the corpus

• Formation of Complex Molecules in Prestellar Cores: A Multilayer Approach (2017, methodology): “Vasyunin & Herbst (2013b) proposed that reactions of radiative association may be important for the formation of some terrestrial-type organic molecules such as dimethyl ether.”
• Complex organic molecules in protoplanetary disks (2013, methodology): “Recently, Vasyunin & Herbst (2013) suggested reactive desorption from grain surfaces followed by radiative associationin the gas phase as a potential mechanism for the production of several complex molecules recently detected in dark clouds and prestellar cores (Bacmann et al. 2012; Cernicharo et…”
• Binding energies: New values and impact on the efficiency of chemical desorption (2017, methodology): “Although the mechanism has been included in astrochemical models (for instance Garrod et al. 2007; Vasyunin & Herbst 2013; Wakelam et al. 2014), its efficiency has been a free parameter.”
• Formation of complex organic molecules in cold objects: the role of gas-phase reactions (2015, background): “Two recent models have been published trying to explain these new observations, assuming that the detected COMs are present inside the cold and dense core (Vasyunin & Herbst 2013, hereinafter VH2013; Chang & Herbst 2014).”
• THE ORIGIN OF COMPLEX ORGANIC MOLECULES IN PRESTELLAR CORES (2014, background): “Finally, the non detection of CH3OCH3, HCOOCH3 and CH3O is consistent with our and Vasyunin & Herbst (2013) model predictions.”