Positronium formation in a reverse micellar system

The observed decrease in intensity of the long-lived component in positronium decay at a critical surfactant concentration in non-polar solvents, concommitant with the formation of reverse micelles, is described through a diffusion-recombination model. It is emphasized that phenomenological studies, such as the present one, are important for the development of an understanding of positronium formation in liquids for which as yet no satisfactory theory exists, and strengthens the use of positron annihilation as a tool, for the study of the aggregational behaviour of surfactant molecules, the characteristics of which are different for polar and non-polar solvents. (C) 1998 Elsevier Science B.V.