Electron scavenging by SF 6 in the positron spur in nonpolar liquids

Abstract

The positronium (Ps) yield in mixtures of SF 6 with heptane, isoctane, neopentane, and a 0.05 M CCl 4/heptane solution has been determined by means of the lifetime technique. The Ps inhibition constant of SF 6 correlated well with the excess electron rate constant at low SF 6 concentrations. However, minima in the Ps yields were found ( I 3 ≈ 12% at 0.3–0.6 M SF 6 in the pure liquids) at higher SF 6 concentrations. The minima are explained in terms of electron delocalization on the SF 6 molecules resulting in increased probability of a positron SF − 6 reaction to form Ps at higher SF 6 concentrations.