This is the latest version of this eprint.
Douglas, KM orcid.org/0000-0002-3281-3685, Lucas, DI, Walsh, C orcid.org/0000-0001-6078-786X et al. (3 more authors) (2022) The gas-phase reaction of NH₂ with formaldehyde (CH₂O) is not a source of formamide (NH₂CHO) in interstellar environments. The Astrophysical Journal Letters, 937 (1). L16. ISSN 2041-8205
Abstract
The first experimental study of the low-temperature kinetics of the gas-phase reaction of NH₂ with formaldehyde (CH₂O) has been performed. This reaction has previously been suggested as a source of formamide (NH₂CHO) in interstellar environments. A pulsed Laval nozzle equipped with laser-flash photolysis and laser-induced fluorescence spectroscopy was used to create and monitor the temporal decay of NH₂ in the presence of CH₂O. No loss of NH₂ could be observed via reaction with CH₂O, and we place an upper limit on the rate coefficient of <6 × 10¯¹² cm³ molecule¯¹ s¯¹ at 34 K. Ab initio calculations of the potential energy surface were combined with Rice–Rampsberger–Kassel–Marcus (RRKM) calculations to predict a rate coefficient of 6.2 × 10¯¹⁴ cm³ molecule¯¹ s¯¹ at 35 K, consistent with the experimental results. The presence of a significant barrier, 18 kJ mol¯¹, for the formation of formamide as a product, means that only the H-abstraction channel producing NH₃ + CHO, in which the transfer of an H atom can occur by quantum mechanical tunneling through a 23 kJ mol¯¹ barrier, is open at low temperatures. These results are in contrast with a recent theoretical study, which suggested that the reaction could proceed without a barrier and was therefore a viable route to gas-phase formamide formation. The calculated rate coefficients were used in an astrochemical model, which demonstrated that this reaction produces only negligible amounts of gas-phase formamide under interstellar and circumstellar conditions. The reaction of NH₂ with CH₂O is therefore not an important source of formamide at low temperatures in interstellar environments.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | © 2022. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. |
Dates: |
|
Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemistry (Leeds) > Physical Chemistry (Leeds) The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) > Astrophysics (Leeds) |
Funding Information: | Funder Grant number STFC (Science and Technology Facilities Council) ST/T000287/1 MRC (Medical Research Council) MR/T040726/1 STFC (Science and Technology Facilities Council) ST/L000628/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 12 Sep 2022 12:34 |
Last Modified: | 11 Feb 2025 13:55 |
Status: | Published |
Publisher: | IOP Publishing |
Identification Number: | 10.3847/2041-8213/ac8cef |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:190747 |
Available Versions of this Item
-
The gas-phase reaction of NH₂ with formaldehyde (CH₂O) is not a source of formamide (NH₂CHO) in interstellar environments. (deposited 11 Feb 2025 14:56)
- The gas-phase reaction of NH₂ with formaldehyde (CH₂O) is not a source of formamide (NH₂CHO) in interstellar environments. (deposited 12 Sep 2022 12:34) [Currently Displayed]