Knowledge Bank

Four new bands with band heads at $4116.6\backslash AA,4143.5\backslash AA,4172.2\backslash AA$ and $4204.6\backslash AA$ have been obtained in electrical discharges through argon containing a trace of $SiCl4+O2$. These bands are identified and analysed as due to $SiO+$. A rotational analysis has been carried out and it turned out that they represent a $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma -2\Sigma$ transition. The upper $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma$ state of these bands has been found identical with the upper state of the Woods' $bands.1$ Thus the lower $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma$ state of the present bands becomes only $1778cm-1$ above the lower $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma$ state of the Woods' bands, which is reported as the ground state of $SiO+$. It is difficult to understand these two lower $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma$ states in terms of electron configuration. However, we are examining the analysis of the Woods' bands obtained in our lab to clarify this point. These results together with the results on the new system will be presented.