ELECTRON SCAVENGING BY SF6 IN THE POSITRON SPUR IN NON-POLAR LIQUIDS

The positronium (Ps) yield in mixtures of SF6 with heptane, isoctane, neopentane, and a 0.05 M CCl4/heptane solution has been determined by means of the lifetime technique. The Ps inhibition constant of SF6 correlated well with the excess electron rate constant at low SF6 concentrations. However, minima in the Ps yields were found (I3 ≈ 12% at 0.3-0.6 M SF6 in the pure liquids) at higher SF6 concentrations. The minima are explained in terms of electron delocalization on the SF6 molecules resulting in increased probability of a positron SF-6 reaction to form Ps at higher SF6 concentrations. © 1979.