Observation of excited states in the radiolysis of liquid hydrocarbons

Various picosecond and nanosecond pulse radiolysis studies of excited states in alkane and erene liquids are described. In particular, the origin of the excited states is sought after. In alkanes ion neutralization gives rise to excited triplet states of solutes. Singlet energy transfer from excited alkanes to solutes gives rise to the excited singlet states of the solutes. In aromatic liquids both the excited singlet and triplet state of the solvent are observed, and energy transfer to solutes is readily established. The role of ion neutralization in the formation of excited states is proportionally less pronounced as the observed yield of ions is low. However, indirect experiments suggest that the ion neutralization reaction is too rapid for conventional observation, and even in arenes large yields of excited states are formed by ion neutralization.