File(s) under permanent embargo
Adsorption and thermal processing of glycolaldehyde, methyl formate, and acetic acid on graphite at 20 K
journal contribution
posted on 2023-06-08, 21:26 authored by Daren J Burke, Fabrizio Puletti, Paul M Woods, Serena Viti, Ben Slater, Wendy BrownWendy BrownWe present the first detailed comparative study of the adsorption and thermal processing of the three astrophysically important C2O2H4 isomers glycolaldehyde, methyl formate, and acetic acid adsorbed on a graphitic grain analogue at 20 K. The ability of the individual molecule to form intermolecular hydrogen bonds is extremely important, dictating the growth modes of the ice on the surface and the measured desorption energies. Methyl formate forms only weak intermolecular bonds and hence wets the graphite surface, forming monolayer, bilayer, and multilayer ices, with the multilayer having a desorption energy of 35 kJ mol–1. In contrast, glycolaldehyde and acetic acid dewet the surface, forming clusters even at the very lowest coverages. The strength of the intermolecular hydrogen bonding for glycolaldehyde and acetic acid is reflected in their desorption energies (46.8 and 55 kJ mol–1, respectively), which are comparable to those measured for other hydrogen-bonded species such as water. Infrared spectra show that all three isomers undergo structural changes as a result of thermal processing. In the case of acetic acid and glycolaldehyde, this can be assigned to the formation of well-ordered, crystalline, structures where the molecules form chains of hydrogen-bonded moieties. The data reported here are of relevance to astrochemical studies of hot cores and star-forming regions and can be used to model desorption from interstellar ices during the warm up phase with particular importance for complex organic molecules.
History
Publication status
- Published
Journal
The Journal of Physical Chemistry AISSN
1089-5639Publisher
American Chemical SocietyExternal DOI
Issue
26Volume
119Page range
6837-6849Department affiliated with
- Chemistry Publications
Full text available
- No
Peer reviewed?
- Yes
Legacy Posted Date
2015-07-06Usage metrics
Categories
No categories selectedKeywords
Licence
Exports
RefWorks
BibTeX
Ref. manager
Endnote
DataCite
NLM
DC