Rotational Spectrum and 14N-Quadrupole Coupling Constants of Orthofluorobenzonitrile, a Microwave Fouriertransform Study

Seventyseven a-type rotational transitions of Orthofluorobenzonitrile were observed and assigned in the 8 - 25 GHz frequency range. The spectrum was recorded using the high resolution microwave Fourier transform spectrometer constructed at Kiel University. For most transitions the N quadrupole hfs patterns could be fully resolved. The spectroscopic constants obtained by a fit to the observed hfs-center frequencies and to the observed hfs multiplet splittings are: A = 2940.745(12) MHz, B = 1512.699(1) MHz, C = 998.633(1) MHz (rotational constants) and Χ = - 4.114( 17) MHz, X = 0.383(34) MHz ( N quadrupole coupling constants). The rotational spectrum of a low lying vibrational state could be also assigned.