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

We report two complementary experimental investigations of the absorpt ion spectrum of molecular oxygen between 243 and 258 nm. In the first experiment, excitation of O-2 is inferred by detecting oxygen atoms re sulting from chemical reaction. In the second experiment, absorption b y O-2 is observed directly by cavity ring-down spectroscopy. Absorptio n 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 DI ATOM spectral simulation computer program using the best available bra nch intensity formulas. Absolute oscillator strengths are derived for all three systems and compared with values in the literature.