Decay mechanisms of CH3in 3hyphen;methylpentane and 3MPhyphen;d14glasses at 77thinsp;deg;K as indicated by methane yields

摘要

The isotopic methane yields from ggr; irradiation of 3hyphen;methylpentane, 3MPndash;1percnt;CH3I, 3MPhyphen;d14ndash;1percnt;CH3I, and 3MPhyphen;d14ndash;1percnt;CD3I glasses confirm recent evidence from decay kinetics that thermal CH3radicals can abstract H from Cndash;H bonds in hydrocarbon glasses at 77deg;K (plausibly by tunneling) and show that similar abstraction does not occur from Cndash;D bonds. Also, in 3MPhyphen;d14the CH3(formed by the CH3I+eminus;rarr; CH3+Iminus;process) does not decay by radical combination processes (CH3+CH3or CH3+C6D13), implying that decay is by geminate recombination with the Iminus;partner. In the ggr; irradiation of 3MPhyphen;d14ndash;1percnt;CH3I irradiated at 77deg;K,G(CH3D) from hot abstraction by CH3is 0.7; thermal CH3and CD3radicals are able to abstract H from low concentrations of Cndash;H bond isotopic impurities; and the yields of scavengeable electrons and of radicals are substantially different than in 3MPhyphen;h14.