Knowledge Bank

A. 6.65 m vacuum spectrograph has been provided with a photoelectric scanner that is essentially interchangeable with the original plate holder. Performance of the photoelectric scanner will be demonstrated with the Schumann-Runge bands of $O2$ in absorption. Since most of the bands are very diffuse as a result of predissociation and have line widths larger than the instrumental width (13 m{\AA}), the absolute cross sections can be obtained. However, the bands with $\nu \prime$ = 13 & 14 have individual rotational lines with width less than the instrumental width the appropriate method of data reduction for such narrow lines will be discussed. Supported under NASA Grant NSG 5176 to Harvard College.