Knowledge Bank

Several small clusters containing an $H2S$ molecule are being studied with the Balle/Flygare, pulsed beam FTMW spectrometer for comparison with their $H2O$ counterparts. Included so far are $Ar-H2S,Ar3-H2S$, and $N2-H2S$. For $Ar-H2S$ earlier $reports1$ were extended to a second series of transitions, the two now interpretable as $000$ and $101$ internal rotor states of the $H2S$, as published for the $H2O$ in $Ar-H2O.2$ Also, we find $Ar3-H2S$ to be a symmetric top with rotational properties quite similar to those of the $H2O$ analogue. But the $N2-H2S$ dimer appears to differ substantially from $N2-H2O$. The latter has nearly linear N-N-H-O geometry with tunneling quartets caused by interchange of both pairs of $nuclci.3$ The rotational transitions observed for $N2-H2S$, however, are doublets indicating a more or less T-shaped structure with internal rotation, in which only the protons tunnel.