BRANCH INTENSITIES AND OSCILLATOR-STRENGTHS FOR THE HERZBERG ABSORPTION SYSTEMS IN OXYGEN

We report two complementary experimental investigations of the absorption spectrum of molecular oxygen between 243 and 258 nm. In the first experiment, excitation of O-2 is inferred by detecting oxygen atoms resulting from chemical reaction. In the second experiment, absorption by O-2 is observed directly by cavity ring-down spectroscopy. Absorption strengths for the Herzberg I (A(3) Sigma(u)(+)<--X(3) Sigma(g)(-)), Herzberg II (c(1) Sigma(u)(-)<--X(3) Sigma(g)(-)), and Herzberg III (A'(3) Delta(u)<--X(3) Sigma(g)(-)) band systems are modeled with the DIATOM spectral simulation computer program using the best available branch intensity formulas. Absolute oscillator strengths are derived for all three systems and compared with values in the literature.