Microwave Spectrum, Dipole Moment and Quadrupole Coupling Constants of Orthofluoropyridine

Abstract

The rotational spectrum of 2-fluoropyridine has been analyzed in the region between 7 - 40 GHz. The rotational constants for the vibrational ground state are: A = 5870.9 0 MHz, 5 = 2699.9 6 MHz, C = 1849.2 6 MHz. The small inertia defect indicates that the nuclear frame is planar. The two components of the electric dipole moment were obtained from Stark effect measurements: μa = 2.80 ± 0.06 D, μb = 1.87 ± 0.05 D. These values agree well with an INDO closed molecular orbital calculation done at T.I.F.R. From the hyperfine splittings of the rotational line the 14 N nuclear quadrupole coupling constant are determined. The values are : Χaa=-0.02±0.05 MHz, Xbb = -2.80±0.05 MHz, Xcc = +2.82±0.05 MHz