Radiation equilibria pertinent to planetary atmospheres

Radiation equilibria due to ionizing radiation or ultraviolet light, or both, on systems such as air, oxygen, carbon dioxide, and their mixtures are of major importance to planetary atmospheres. To investigate the radiation equilibria in the ultraviolet region, a special “Bromine” lamp has been developed which gives 1017 quanta/sec at 1582 and 1633 A where the latter is the most intense Br line. Since the absorption coefficients of O₂, CO₂, O₃ and other gases are substantial at these wavelengths, radiation equilibria can be obtained in reasonable times (between 1 hr and a few days, depending on conditions) in our 500 ml sample volume. Since the temperature can also be varied, the conditions prevailing in any region of an atmosphere can be simulated. The wall effects are negligible for pressures down to a few mm. The irradiation of O₂, CO, CO₂, N₂ and mixtures of these gases are discussed. The effects of trace amounts of water vapor on the equilibria are noted.