Abstract
Integrated absorption intensities of the Schumann—Runge bands of gaseous 16O2 and 18O2 were measured, using pressure broadening by argon. For the (2, 0) to (6, 0) bands, the observed isotope effect on band intensities is equal to the calculated isotope effect on Franck—Condon factors. For the (7, 0) to (10, 0) bands, deviations of the observed isotope effect from that computed may be due to failure of the Morse potential function used in the computations, or to experimental difficulties caused by overlapping of bands.