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Title: Infrared spectroscopy of Mg–CO{sub 2} and Al–CO{sub 2} complexes in helium nanodroplets

The catalytic reduction of CO{sub 2} to produce hydrocarbon fuels is a topic that has gained significant attention. Development of efficient catalysts is a key enabler to such approaches, and metal-based catalysts have shown promise towards this goal. The development of a fundamental understanding of the interactions between CO{sub 2} molecules and metal atoms is expected to offer insight into the chemistry that occurs at the active site of such catalysts. In the current study, we utilize helium droplet methods to assemble complexes composed of a CO{sub 2} molecule and a Mg or Al atom. High-resolution infrared (IR) spectroscopy and optically selected mass spectrometry are used to probe the structure and binding of the complexes, and the experimental observations are compared with theoretical results determined from ab initio calculations. In both the Mg–CO{sub 2} and Al–CO{sub 2} systems, two IR bands are obtained: one assigned to a linear isomer and the other assigned to a T-shaped isomer. In the case of the Mg–CO{sub 2} complexes, the vibrational frequencies and rotational constants associated with the two isomers are in good agreement with theoretical values. In the case of the Al–CO{sub 2} complexes, the vibrational frequencies agree with theoretical predictions; however, themore » bands from both structural isomers exhibit significant homogeneous broadening sufficient to completely obscure the rotational structure of the bands. The broadening is consistent with an upper state lifetime of 2.7 ps for the linear isomer and 1.8 ps for the T-shaped isomer. The short lifetime is tentatively attributed to a prompt photo-induced chemical reaction between the CO{sub 2} molecule and the Al atom comprising the complex.« less
Authors:
 [1] ;  [2] ; ;  [3]
  1. Spectral Energies, LLC, Dayton, Ohio 45431 (United States)
  2. Energy Technology and Materials Division, University of Dayton Research Institute, Dayton, Ohio 45469 (United States)
  3. Air Force Research Laboratory, Aerospace Systems Directorate, Wright-Patterson Air Force Base, Ohio 45433 (United States)
Publication Date:
OSTI Identifier:
22415746
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION SPECTROSCOPY; ATOMS; CARBON DIOXIDE; CATALYSTS; CHEMISTRY; COMPARATIVE EVALUATIONS; COMPLEXES; HELIUM; HYDROCARBONS; INFRARED SPECTRA; ISOMERS; LIFETIME; MASS SPECTROSCOPY; METALS; MOLECULES; REDUCTION