The I, I′, and I″ absorption bands of O 2 in the region 790–865 Å

Abstract

The absorption spectra of 16O 2 and 18O 2 in the wavelength region 790–865 Å have been photographed with a 6.65-m vacuum spectrograph. The bands are diffuse and most of them are classified as members of three vibrational progressions, I, I′, and I″, which originate from the v = 0 level of the ground state of oxygen. Absolute vibrational quantum number assignments are made for each of these progressions based on isotope shift analysis, and the vibrational constants of their upper electronic states are reported for 16O 2 and 18O 2. The similarity in vibrational constants between these electronic states and those for the a 4Π ui state of O 2 +, as well as their quantum defects suggest that they are Rydberg states. In addition, the magnitude of their spin-orbit splitting and the rotational structure for some of these bands indicate that the upper electronic state for each of these three progressions has 3Π u symmetry.