title: Gas phase measurements of mono-fluoro-benzoic acids and the dimer of 3-fluoro-benzoic acid.
abstract: 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(+)) = 1151.8(5), B(0(+)) = 100.3(5), C(0(+)) = 87.64(3) MHz and A(0(-)) = 1152.2(5), B(0(-)) = 100.7(5), C(0(-)) = 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: Jet Propulsion Laboratory, California Institute of Technology, Pasedena, California 91106, USA.
authors: Adam M
authors: AM
authors: Daly
authors: Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, USA.
authors: Spencer J
authors: SJ
authors: Carey
authors: Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, USA.
authors: Aaron M
authors: AM
authors: Pejlovas
authors: Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, USA.
authors: Kexin
authors: K
authors: Li
authors: Department of Chemistry and Biochemistry, Kennesaw State University, Kennesaw, Georgia 30144, USA.
authors: Lu
authors: L
authors: Kang
authors: Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, USA.
authors: Stephen G
authors: SG
authors: Kukolich