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8436486 
Journal Article 
Relevance of the concentration dependence of methyl radical formation from methyl bromide solutions to the distribution of ion-pair separation distances in irradiated hydrocarbons 
Warman, JM; Rzad, SJ 
1970 
Yes 
Journal of Chemical Physics
ISSN: 0021-9606
EISSN: 1089-7690 
52 
2 
485-490 
English 
A radiochromatographic technique for measuring the yields of methyl radicals formed on electron capture by methyl bromide in irradiated liquid hydrocarbons is described. G(CH3) has been measured in n-hexane, cyclohexane, and iso-octane from 3×10-6 to 0.3M CH 3Br. Below 3×10-6 the yields are described by the equation G(CH3)=Gfi+K(CH3Br)1/2 in agreement with theory. The values of GH (free-ion yield) determined are 0.12, 0.13, and 0.36 for n-hexane, cyclohexane, and isooctane, respectively. Over the entire concentration range studied, G(CH3) can be described by the empirical expression G(CH3)=Gfi+(G gi(αCH3Br[CH3Br])1/2/ {1+(αCH3[CH3Br])1/2}). A value of approximately 4 is found for the yield of geminately recombining ion pairs for the three hydrocarbons. It is argued from the high-concentration data that the distribution of thermalization distances are closely similar for the different hydrocarbons, in contradiction to the predicted longer distances in iso-octane required to explain the high free-ion yield.