Knowledge Bank

The absorption spectra of $\mathrm{<mrow\; data-mjx-texclass="ORD">16</mrow>}O2$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">18</mrow>}O2$ in the 650 - 1000 \AA region were photographed in the second order of the helium continuum with a 6.65 m vacuum spectrograph. The $\mathrm{<mrow\; data-mjx-texclass="ORD">16</mrow>}O2$ bands in this region were first observed by Price and $Collins1$ and later by Tanaka and $Takamine2$ but many bands are still unclassified. Although the majority of bands are diffuse and in some cases strongly perturbed, we were able to observe the triplet nature of many of these bands. We will report at this time primarily on the bands in the 730 - 860 \AA region where we have classified several members of the Rydberg series which converge to the a $\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}\Pi ui$ state of $O2+$. The state designation, accurate vibrational quantum number assignments based on isotope shift analysis, and the vibrational constants for these Rydberg states will be presented.