Absorption Coefficients of Oxygen in the 1060–580-Å Wavelength Region

Abstract

Absorption coefficients of oxygen have been measured in the 1060–580-Å wavelength region using a continuum background at a bandwidth of 0.5 Å. The background light source is a repetitive discharge through helium which produces the Hopfield continuum. Absorption bands and underlying dissociation and ionization continua are observed throughout this wavelength region. The continuum rises linearly from ≲20 cm—1 at the first ionization threshold (1026.7 Å), to about 300 cm—1 at 840 Å where the continuum begins to rise more sharply. Toward shorter wavelengths, there are three maxima in the continuum at about 800, 720, and 610 Å with approximate k values of 850, 850, and 1000 cm—1, respectively. The absorption bands appear diffuse, probably due to pre-ionization, and maximum k values of up to 1700 cm—1 are found. Dissociation and ionization processes responsible for the continua are discussed, and comparison is made with previous absorption coefficient measurements.