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Title: Gas phase measurements of mono-fluoro-benzoic acids and the dimer of 3-fluoro-benzoic acid

The microwave spectrum of the mono-fluoro-benzoic acids, 2-fluoro-, 3-fluoro-, and 4-fluoro-benzoic acid have been measured in the frequency range of 4-14 GHz using a pulsed beam Fourier transform microwave spectrometer. Measured rotational transition lines were assigned and fit using a rigid rotor Hamiltonian. Assignments were made for 3 conformers of 2-fluorobenzoic acid, 2 conformers of 3-fluorobenzoic acid, and 1 conformer of 4-fluorobenzoic acid. Additionally, the gas phase homodimer of 3-fluorobenzoic acid was detected, and the spectra showed evidence of proton tunneling. Experimental rotational constants are A(0{sup +}) = 1151.8(5), B(0{sup +}) = 100.3(5), C(0{sup +}) = 87.64(3) MHz and A(0{sup −}) = 1152.2(5), B(0{sup −}) = 100.7(5), C(0{sup −}) = 88.85(3) MHz for the two ground vibrational states split by the proton tunneling motion. The tunneling splitting (ΔE) is approximately 560 MHz. This homodimer appears to be the largest carboxylic acid dimer observed with F-T microwave spectroscopy.
Authors:
 [1] ; ; ; ;  [2] ;  [3]
  1. Jet Propulsion Laboratory, California Institute of Technology, Pasedena, California 91106 (United States)
  2. Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721 (United States)
  3. Department of Chemistry and Biochemistry, Kennesaw State University, Kennesaw, Georgia 30144 (United States)
Publication Date:
OSTI Identifier:
22415635
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 14; 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; BENZOIC ACID; DIMERS; FOURIER TRANSFORMATION; GHZ RANGE; HAMILTONIANS; MHZ RANGE; MICROWAVE RADIATION; MICROWAVE SPECTRA; PROTONS; SPECTROSCOPY; TUNNEL EFFECT; VIBRATIONAL STATES