Experimentally determined oscillator strengths and linewidths for the Schumann-Runge band system of molecular oxygen—I. The (6-0)–(14-0) bands

Abstract

Experimental oscillator strengths and predissociated linewidths have been measured at room temperature for the (6-0)–(14-0) Schumann-Runge bands of molecular oxygen using the Adelaide 6 m vacuum u.v. monochromator operated at a resolution of about 0.06 Å. Photoelectric detectors were used to measure the u.v. absorption at two different gas pressures for 138 groups of rotational lines distributed throughout the (6-0)–(14-0) bands and the resulting data were interpreted using an equivalent width type of analysis. Experimental measurements of the variation with N″ of the oscillator strengths within each band have been obtained for the first time. Measured oscillator strengths are found to be somwhat higher in general than previously reported values with a slightly faster decrease as N″ increases than is predicted theoretically. The mean predissociated linewidths obtained for each band show a smooth variation with v′, agreeing well with other results for v′=12−14 and lying between previously reported experimental and theoretical values for v′=6−9. The present work provides results which can be used to construct highly accurate synthetic absorption profiles for studies of the atmospheric absorption of u.v. radiation by the Schumann-Runge bands.