Fourier transform spectroscopy of the O-2 Herzberg bands - I. Rotational analysis

The absorption spectra of the O-2 Herzberg band systems (A(3)Sigma(u)(+)-X( 3)Sigma(g)(-), c(1)Sigma(u)(-)X(3)Sigma(g)(-), and A' (3)Delta(u)-X(3)Sigma (g)(-)) lying in the wavelength region 240-300 nm were reinvestigated. The coupling of a long absorption cell and a high-resolution Fourier transform spectrometer has allowed the observation of numerous weak lines which were not reported previously. From the rotational analysis of the line positions , determined with an accuracy of 0.005 cm(-1), the molecular constants of t he A(3)Sigma(u)(+), v = 0-12, c(1)Sigma(u)(-), v = 2-19, and A' (3)Delta(u) , v = 2-12 levels are improved significantly, The interaction between the A and c states is described quantitatively. A new interpretation of the pert urbations observed in the energy region close to the dissociation limit is given which involves a weakly bound (3)Pi(u) state as the most probable per turbing state. (C) 1999 Academic Press.