Spectroscopic feature of the ozone molecule with considerable structure related to vibrational levels in the ozone molecule occurring at a wavelength around 600 nm, or an energy of 2 eV. The absorption bands lead to photodissociation of an ozone molecule into an O2 molecule and an oxygen atom. The bands were first identified in the atmospheric spectrum by Chappuis (1880) and have been used to measure ozone in the atmosphere.