Knowledge Bank

The absorption spectrum of $H2S2$ in the range 250 to $4000cm-1$ has been reviewed under medium resolution in the gaseous and liquid state. $D2S2$ has been prepared and its infrared spectrum measured for the first time. The design and use of an absorption cell for unstable gases will be discussed. No new absorption bands were observed for $H2S2$, but more structure could be resolved in each band than in previous $studies.1,2$ The features of the torsional band at $416cm-1$ are of particular interest. The $\nu 5,\nu 6$, and $\nu 1+\nu 5$ bands of $D2S2$ could be measured, and the torsional band $\nu 4$ was observed. In addition, the torsional band of the partially deuterated species HSSD was observed. The rotational constant (A-B) for both deuterated species agrees well with values calculated from structure parameters of $H2S2$ determined by microwave studies and electron diffraction. A force constant analysis of the data will be discussed.