Knowledge Bank

A second isomer of OCS-CS$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$ complex, with a nonplanar cross-shaped structure, has been studied for the first time by analysing an infrared band in the region of the OCS stretching vibration (2062 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$). This isomer has C symmetry and the observed band consists of purely c-type rotational transitions. The ground state rotational parameters are found to be A=0.07306 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$, B=0.03325 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$ and C=0.02879 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$, in good agreement with a previous semi-empirical calculation. \textbf{7}, 487 (2005).} In addition, a hybrid band with a- and b-type rotational transitions has been assigned to be due to the known planar form of OCS-CS$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$, as previously studied by microwave spectroscopy.$a$ The spectra were recorded using a rapid-scan tunable diode laser spectrometer to probe a pulsed supersonic jet expansion. Calculations indicate that the planar isomer of OCS-CS$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$ is the lowest in energy, in contrast to CO$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$-CS$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$ where the crossed form is believed to be the lowest. \textbf{102}, 6904 (1998).}