Secondary effects due to the presence of sulfur hexafluoride in hydrocarbon radiolysis

SF/sub 6/, used as an electron scavenger in the radiolysis of gaseous ethylene and propane, is found to decompose with a yield close to the yleld of electrons. The products of SF/sub 6/ decomposition do not compete with parent molecules for electrons. The radiolysis of gaseous ethylene-cis-2-butene-1,3- butadiene-SF/sub 6/ mixtures reveals that secondary products, derived from SF/sub 6/, react with butadiene and act as chain carriers of cis-trans isomerization. Both processes involve the same radical species. A free-radical mechanism is estabished on the basis of photoelectron and vacuum-uv photolysis experiments. (auth)