Collision-Induced Absorption of Gaseous Oxygen in the Herzberg Continuum

The values of the binary absorption coefficient for gaseous molecular oxygen in the region of the Herzberg photodissociation continuum (200–230 nm) have been measured in the temperature range 110–295 K. The induced absorption of oxygen in the 200–220 nm spectral region was found to result from two bands with quite different temperature dependence of their intensity: for the Herzberg III band the values of the binary absorption coefficient increase by ~ 50% as the temperature decreases from 295 to 110 K, while for the other band no distinct temperature dependence of the binary absorption coefficient was observed. A transition dipole moment function including both short-range term (overlap of the electron shells of interacting molecules) and long-range term (interaction of the transient quadrupole moments) is proposed to describe the temperature dependence of the binary absorption coefficients in the Herzberg III band.