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Title: Assignment of the Fundamental Modes of Hydroxyacetone Using Gas-Phase Infrared, Far-Infrared, Raman, and ab Initio Methods: Band Strengths for Atmospheric Measurements

Hydroxyacetone (acetol) is a simple organic molecule of interest in both the astrophysical and atmospheric communities, having recently been observed in biomass burning events, as well as a known degradation product of isoprene oxidation. However, its vibrational assignment has never been fully completed, and few quantitative data are available for its detection via infrared spectroscopy. Our recent acquisition of both the pressure-broadened gas-phase data and the far-IR spectra now allow for unambiguous assignment of several (new) bands. In particular, the observed C-type bands of several fundamentals (particularly in the far-infrared) and a few combination bands demonstrate that the monomer is in a planar (Cs) conformation, at least a majority of the time. As suggested by other researchers, the monomer is a cis-cis conformer stabilized by an intramolecular O—H···O=C hydrogen bond forming a five-membered planar ring structure. Band assignments in the Cs point group are justified (at least for a good fraction of the molecules in the ensemble) by the presence of the C-type bands. The results and band assignments are well confirmed by both ab initio MP2-ccpvtz calculations as well as GAMESS (B3LYP) theoretical calculations. In addition, using vetted methods for quantitative measurements, we report the first IR absorption bandmore » strengths of acetol (also in electronic format) that can be used for atmospheric monitoring and other applications.« less
Authors:
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Publication Date:
OSTI Identifier:
1290389
Report Number(s):
PNNL-SA-117947
Journal ID: ISSN 1089-5639; 453040142
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory; Journal Volume: 120; Journal Issue: 30
Publisher:
American Chemical Society
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation (NA-20)
Country of Publication:
United States
Language:
English