Knowledge Bank

The pure rotational spectrum of KSH (X$\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}$A) has been measured using millimeter-wave direct-absorption techniques for the first time. KSH was synthesized by the reaction of potassium vapor and H$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$S in the presence of a direct current discharge. Five rotational transitions in the frequency range of 260$\{-300$ GHz were recorded for both KSH and KSD in their ground electronic states. The K-ladder structure indicates C symmetry, and therefore a bent molecule. Accurate rotational and hyperfine constants have been determined from a global fit including previously measured microwave spectra. A comparison of KSH to other alkali metal hydrosulfides will be presented.