On the involvement of geminate pairs in radiation-induced conductivity of polystyrene

Basic parameters of the generalized Rose-Fowler-Weisberg theory were experi mentally determined for polystyrene. The obtained data were used to compreh ensively analyze the evolution of geminate pairs in this polymer. It was sh own that the generation of the prompt component of radiation-induced conduc tivity occurs by the trapping mechanism with two charge carrier states invo lved, the quasi-free and trapped. This generation under equilibrium transpo rt conditions (diffusivity and mobility of carriers are constant) reportedl y ensured by the geminate recombination itself was not observed in a real e xperiment. With allowance for dispersive transport of holes (the major carr iers), the lifetime of geminate pairs were found to be as long as a few hun dred of milliseconds at 300 K. The published data on the formation and deca y kinetics in doped polystyrene upon its pulse radiolysis or photolysis wer e thoroughly analyzed. It was shown that, at ultrashort times before locali zation of generated carriers, the contribution of electrons to the observed conductivity prevails, although the basic contribution is made by holes in later times.