Carbon Atom Reactivity with Amorphous Solid Water: H2O-Catalyzed Formation of H2CO

The Journal of Physical Chemistry Letters, vol. 12, pp. 10854–10860

Abstract

High Resolution Image Download MS PowerPoint Slide We report new computational and experimental evidence of an efficient and astrochemically relevant formation route to formaldehyde (H 2 CO). This simplest carbonylic compound is central to the formation of complex organics in cold interstellar clouds and is generally regarded to be formed by the hydrogenation of solid-state carbon monoxide. We demonstrate H 2 CO formation via the reaction of carbon atoms with amorphous solid water. Crucial to our proposed mechanism is a concerted proton transfer catalyzed by the water hydrogen bonding network. Consequently, the reactions 3 C + H 2 O → 3 HCOH and 1 HCOH → 1 H 2 CO can take place with low or without barriers, contrary to the high-barrier traditional internal hydrogen migration. These low barriers (or the absence thereof) explain the very small kinetic isotope effect in our experiments when comparing the formation of H 2 CO to D 2 CO. Our results reconcile the disagreement found in the literature on the reaction route C + H 2 O → H 2 CO.

Authors 7

1. Germán Molpeceres corresponding

   University of Stuttgart

   Affiliation as printed

   Institute for Theoretical Chemistry, University of Stuttgart, 70569 Stuttgart, Germany

2. Johannes Kästner

   University of Stuttgart

   Affiliation as printed

   Institute for Theoretical Chemistry, University of Stuttgart, 70569 Stuttgart, Germany

3. G. Fedoseev Aachen Laboratory for Astrophysics, Leiden Observatory

   Leiden University · Leiden Observatory · Ural Federal University

   Affiliation as printed

   Laboratory for Astrophysics, Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands

   Research Laboratory for Astrochemistry, Ural Federal University, Kuibysheva St. 48, 620026 Ekaterinburg, Russia

4. D. Qasim Aachen Laboratory for Astrophysics, Leiden Observatory

   Leiden University · Leiden Observatory

   Affiliation as printed

   Laboratory for Astrophysics, Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands

5. Richard Schömig

   University of Stuttgart

   Affiliation as printed

   Institute for Theoretical Chemistry, University of Stuttgart, 70569 Stuttgart, Germany

6. H. Linnartz Aachen Laboratory for Astrophysics, Leiden Observatory

   Leiden University · Leiden Observatory

   Affiliation as printed

   Laboratory for Astrophysics, Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands

7. Thanja Lamberts corresponding Aachen Laboratory for Astrophysics, Leiden Observatory Leiden Institute of Chemistry, Gorlaeus Laboratories

   Leiden University · Leiden Observatory

   Affiliation as printed

   Laboratory for Astrophysics, Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands

   Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands