Spin correlation in the geminate recombination of radical ions in hydrocarbons. Part 2—Time resolved single-photon counting study of the magnetic field effect

Abstract

Pulse shapes of scintillations produced by beta-particles have been measured by time-resolved single-photon counting. Magnetic fields and deuteration of the solute enhance the fluorescence of para-terphenyl and other solutes. This is due to electron-nuclear hyperfine interaction in the radical ions which interconverts the singlet and triplet wave-functions of the ion pairs. The extent of the effect gives a measure of the relative initial yields of singlet and triplet ion pairs. The magnetic field effects very considerably among the solvents studied—n-hexane, iso-octane, cyclohexane, methyl-cyclohexane, trans-decalin, mixed decalins, squalane and benzene.