Phase shift of quantum oscillations in the recombination luminescence of spin-correlated radical ion pairs

The phas shift of quantum oscillations observed in the recombination fluorescence of the (diphenylsulfide-d10)+/(p-terphenyl-d14)− radical ion pair in isooctane has been detected experimentally. The shift is caused by the delay in (diphenylsulfide-d10)+ formation in the reaction of solvent holes with a diphenylsulfide molecule. Comparison with a theoretical model has given for the rate constant of isooctane hole capture by diphenylsulfide molecules the value (3.5±1) × 1010M−1s−1 which exceeds the diffusion-controlled one. The fraction of singlet-correlated pairs in the track has been estimated from the oscillation amplitude to be approximately 35%.