Collision-induced absorption of O2 in the Herzberg continuum

Using a one meter normal incidence grating monochromator, the total absorption of radiation for O₂ has been reinvestigated between 2000–2500 Å. The absorption cross sections of O₂ and O₄ are then derived from total absorption measurements and compared with other available data. Additional measurements of O₂ absorption have been made in the presence of Ar which does not absorb in this spectral region and is chemically inactive with O₂. It is found that the absorption of oxygen increases in the presence of Ar, which is interpreted as due to the formation of O₂-Ar dimers. The significance of these measurements is discussed.