LABORATORY DETECTION OF C5S BY PULSED-DISCHARGE-NOZZLE FOURIER-TRANSFORM MICROWAVE SPECTROSCOPY

The rotational spectrum of C5S in the X 1SIGMA+(v = 0) ground state ha s been observed for the first time using a Fabry-Perot-type Fourier tr ansform microwave spectrometer combined with a pulsed discharge nozzle . C5S was generated by a discharge in a mixture of CS2 and C2H2 dilute d in Ar, and subsequently cooled down to a few kelvins in a supersonic jet. Eight rotational transitions of (C5S)-S-32 have been observed in the 5-20 GHz region. Three lines for the less abundant S-34 species h ave also been detected to confirm the carrier of the observed lines to be C5S. Determined spectroscopic constants will allow a deep radio as tronomical search for C5S in interstellar clouds and circumstellar env elopes of late-type stars.