Knowledge Bank

A band system of the IO molecule, first observed by Coleman, Gaydon and $Vaidya1$ in emission from an oxyhydrogen flame to which methyl iodide was added, has been photographed under high resolution using a 21 ft. concave grating spectrograph. Approximately forty bands have been observed in the region 4000 to 7000 {\AA}. The rotational structure of the bands indicates that the transition is of the type $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Pi 2\Pi$. The analysis of the bands and the molecular constants of IO will be discussed.