On the application of Onsager theory to 'warm liquids' irradiated by gamma -rays

Data on the free ion yield produced by gamma -radiolysis of neopentane (NP), 2,2,4,4-tetramethylpentane (TMP), tetramethylsilane (TMS), tetramethylgermanium (TMG), and tetramethyltin (TMSn) are analyzed using Onsager theory. Four distributed functions describing the separation distance between electron-ion pairs at thermalization were considered: a delta function (DELTA), an exponential function (EXP), an exponential modified by a first power of r (R1EXP), and an exponential modified by a quadratic power of r (R2EXP). With a suitable choice of adjustable parameters, G( infinity ) and rho , where G( infinity ) is the number of electron-ion pairs initially produced per every 100 eV released in the sample and rho is the mean thermalization distance, all four distributions approximately describe the data. For NP, TMP, and TMG, the data are best described by R1EXP; for TMSn, R2EXP is best.<>