Correlation between pulse radiolysis and positron annihilation techniques data

Abstract

The inhibition and enhancement constants for positronium (Ps) formation in water for 50 solutes are reported; they are shown to be strongly correlated to the rate constants for hydrated electron, k e aq − or for OH scavenging, k OH, measured in pulse radiolysis experiments, respectively. While most of the solutes appear able to inhibit completely Ps formation at high enough concentration, some lead to limited inhibition only, and the fraction ƒ of Ps thus suppressed is characteristic of the solvent. These data lend support to the spur model of Ps formation and suggest that the fully solvated particles are not likely to be involved in this process. On this basis, a provisional model for Ps formation is proposed and discussed.