Sub-millimeter spectroscopy of BaS (X1Σ+)

The pure rotational spectrum of BaS (X1Σ+) has been recorded in the frequency range 355-396 GHz using direct absorption methods. Data were recorded for six isotopomers: 138Ba32S, 137Ba32S, 136B32S, 135Ba32S, 134Ba32S, and 138Ba34S, in vibrational states ranging from v = 0 to v = 6. This work is an extension of past microwave and millimeter studies. Revised spectroscopic constants have been established for the six species. The dissociation energy for 138Ba32S is estimated to be DEhc∼ 42 392 cm−1.