The Wulf bands of oxygen

Abstract

The Wulf bands of oxygen in the 240–290 nm spectral region are caused by collision-induced absorption of the Herzberg III ( A′ 3 Δ u – X 3 Σ − g ) system. These bands had been previously attributed to the oxygen dimer, (O 2) 2. Under atmospheric conditions the Wulf bands are thus the long-wavelength extension of the Herzberg continuum. Absorption of solar radiation by the Wulf bands may be an additional source of NO in the stratosphere.