Photolysis of CH4-NH3 mixtures and PH3 as models for the photochemical transformations on the primitive earth and Jupiter

Methane, ammonia and phosphine are some of the possible constituents of the atmospheres of the Jovian planets and their satellites. Photolysis of NH3 in the presence of CH4 at 185 nm in the temperature range of 25 C to -100 C results in the decomposition of CH4. The reaction is inhibited by added H2 or SF6. These findings are consistent with the reaction of hot hydrogen atoms with CH4 to give the CH3 radical. P2H4 is the initial product formed by the photolysis of PH3 at 206 nm. Kinetic studies established that it is the intermediate in the formation of P4 from PH3. The potential significance of these reactions to the atmospheric photochemistry of the Jovian planets and moons is discussed.