Knowledge Bank

Two new band systems of the SO molecule have been photographed with high dispersion spectrographs and have been analysed. The first system, composed of two strong red degraded double headed bands is observed in emission at 9,550 and $9,630\backslash AA$ in the afterglow produced when a mixture of COS and $O2$ is pumped rapidly through a microwave discharge. The rotational analysis shows these bands to be respectively the (0,0) and (1,1) bands of the b $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Sigma +-X3\Sigma -$ transition of the SO molecule. Weak (2,2) and (0,1) bands are also observed at low dispersion at 9,710 and 10,800 {\AA} respectively. The second system is observed in absorption around $2400\backslash AA$ at short delay times after the flash photolysis of mixtures of COS, $O2$ and Ar. This system previously attributed to $SO\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}1$ has been analysed and is shown to be due to a $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}II(a)-X3\Sigma$ transition of SO arising from the $v\prime \prime =0$ level. The vibrational numbering of the upper $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}II$ state is so far undetermined.