Nanosecond Pulse Radiolysis Studies of the Reaction of Ions in Cyclohexane Solutions

The positive and negative ions of biphenyl and anthracene are observed in the pulse radiolysis of solutions of these molecules in deaerated cyclohexane. Most of the ions (G∼0.9) decay rapidly over 50 nsec, while a small yield (G∼0.2) decays over many microseconds. The rapid decay is indicative of a heterogeneous kinetic condition, namely the formation of ion pairs. The product of the neutralization of these ions is the triplet state of the molecule (Gtriplet∼1 at high concentrations), and a small yield of luminescence. This luminescence may indicate that a small yield ( < 0.25) of singlet excited states is formed. A large yield (Gtriplet > 2) of triplet excited states, is formed in less than 1 nsec. It is suggested that these excited states are formed directly from subexcitation electrons.