Photochemistry of acetylene at 1849 Å

The photochemistry of acetylene at 1849 A has been studied over the pressure range from 13 to 2660 N m−2 (0.1–20 Torr). The quantum yield of diacetylene formation has been measured as a function of C2H2 pressure and the partial pressures of He and N2. The quantum yield of H2 formation has also been obtained. It was concluded that the quantum yield for C2H2→hνC2H+H is 0.06 and that for C2H2→hνC2+H2 is 0.1. The remaining process is the formation of a metastable acetylene which reacts either with C2H2 to form C2H radicals or is deactivated by collisions with the walls or inert gases. The C2H radicals react 0.240±0.015 times as fast with C2H6 and 0.469±0.041 times as fast with C3H8 as with C2H2. The role of acetylene photolysis in the Titan atmosphere is briefly discussed.

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