Predissociation of oxygen in the B 3Σ-u state

The predissociation linewidths and level shifts of vibrational levels of three oxygen isotopic molecules 16O 2, 16O 18O, and 18O 2 arising from the interactions of the B 3Σ u -~ state with the four repulsive states 5Π u, 3Σ u +, 3Π u, and 1Π u, have been calculated. A set of parameters characterizing these interactions has been determined. Good agreement between calculated and experimental predissociation widths and shifts has been obtained for all the three isotopic molecules. © 1992 American Institute of Physics.published_or_final_versio

Predissociation linewidths of the (3,0)-(11,0) Schumann-Runge absorption bands of 18O2 and 16O 18O in the wavelength region 180-196 nm

Predissociation linewidths of the (3,0)-(11,0) Scbumman-Runge bands of 18O 2 and 16O 18O in the wavelength region 180-196 nm have been obtained from the published measurements of the absolute absorption cross sections of Yoshino et al. [Planet. Space Sci. 36, 1201 ( 1988); 37, 419 (1989)] and spectroscopic constants of these molecules of Cheung et al. [J. Mol. Spectrosc. 131, 96 ( 1988); 134, 362 (1989)]. The linewidths are determined as parameters in the nonlinear least-squares fitting of calculated to measured cross sections. Predissociation maxima are found at upper vibrational levels with v′ = 4 ,7, and 10 for 18O 2 and for 16O 18O. Our predissociation linewidths are mostly greater than previous experimental values for both isotopic molecules. © 1990 American Institute of Physics.published_or_final_versio

Predissociation linewidths of the (1,0)-(12,0) Schumann-Runge absorption bands of O2 in the wavelength region 179-202 nm

A nonlinear least-squares method of retrieving predissociation linewidths from the experimental absolute absorption cross sections of Yoshino et al. [Planet. Space Sci. 31, 339 (1983)] has been applied to the (1,0)-(12,0) Schumann-Runge bands of oxygen. Predissociation linewidths deduced for the Schumann-Runge bands are larger than the theoretical predictions of Julienne [J. Mol. Spectrosc. 63, 60 (1976)] and the latest measurements of Lewis et al. [J. Quant. Spectrosc. Radiat Transfer 36, 187 (1986)]. The larger linewidths found will have an impact on calculations of solar flux penetration into the Earth's atmosphere and of the photodissociation rates of trace species in the upper atmosphere. Systematic variation of predissociation linewidths with rotational quantum number is observed in the bands (v′,0) with v′ = 6, 8, 9, 11, and 12. © 1990 American Institute of Physics.published_or_final_versio