The millimeter- and submillimeter-wave spectrum of HC3N in the ground and vibrationally excited states

The pure rotational spectrum of the astrophysically very important linear molecule cyanoacetylene, HC3N, in the ground and vibrationally excited stares has been studied in selected regions from 118 to 814 GHz using the Cologne terahertz spectrometer. Vibrational satellites appendant to the following vibrational states have been recorded and analyzed (v(4), v(5), v(6), v(7)): (0, 0, 0, 1), (0, 0, 0, 2), (0, 0, 1, 0), (0, 0, 1, 1), (1, 0, 0, 0), (1, 0, 0, 1), and the Fermi resonance systems (0, 1, 0, 0)/(0, 0, 0, 3) and (1, 0, 0, 2)/(0, 2, 0, 0)(0e). With the exception of the latter resonance system, all states have been fitted within experimental accuracy. This work provides improved rest frequencies for the astronomical community and may also be beneficial in the improvement of global fits. (C) 2000 Academic Press.