Deep-UV high resolution cavity ring-down spectroscopy of the Schumann-Runge bands in 16O2 and 18O2 at wavelengths 197-203Â nm

With the use of a novel titanium:sapphire laser source delivering, upon fourth harmonic generation, narrowband and tunable radiation in the deep-UV, spectroscopic studies were performed on weak Schumann-Runge bands of oxygen. Improved values for rotational and fine structure molecular parameters for the B3Σu-, v = 0-2 states of 16O2 were determined, as well as values for the v = 0-1 states in 18O2. Signal detection was accomplished via cavity ring-down spectroscopy.