Cavity ring-down measurement of the O2-O2 collision-induced absorption resonance at 477 nm at sub-atmospheric pressures

The collision-induced absorption feature X3Σg-(v=0)+X3Σg-(v=0)→a1Δg(v=0)+b1Σg+(v=0) in the wavelength range 467-490 nm has been investigated by means of the laser-based cavity-ring-down technique at pressures between 0 and 1000 hPa and at T=294 K. Pressure and wavelength dependent cross sections have been determined leading to a band-integrated value of (2.18±0.04)x10-43 cm4 molecule-2. Special care has been given to the wings of the resonance profile and the Rayleigh extinction was taken into account.