Terahertz spectroscopy of hydrogen sulfide

Pure rotational transitions of hydrogen sulfide (H2S) in its ground and first excited vibrational states have been recorded at room temperature. The spectrum comprises an average of 1020 scans at 0.005 cm(-1) resolution recorded in the region 45-360 cm(-1) (1.4 to 10.5 THz) with a globar continuum source using a Fourier transform spectrometer located at the AILES beamline of the SOLEIL synchrotron. Over 2400 rotational lines have been detected belonging to ground vibrational state transitions of the four isotopologues (H2S)-S-32, (H2S)-S-33, (H2S)-S-34, and (H2S)-S-36 observed in natural abundance. 65% of these lines are recorded and assigned for the first time, sampling levels as high as J=26 and K-a=17 for (H2S)-S-32. 320 pure rotational transitions of (H2S)-S-32 in its first excited bending vibrational state are recorded and analysed for the first time and 86 transitions for (H2S)-S-34, where some of these transitions belong to new experimental energy levels. Rotational constants have been fitted for all the isotopologues in both vibrational states using a standard effective Hamiltonian approach. Comprehensive comparisons are made with previously available data as well as the data available in HITRAN, CDMS, and JPL databases. The 91 transitions assigned to (H2S)-S-36 give the first proper characterization of its pure rotational spectrum. (C) 2013 Published by Elsevier Ltd.