Biphasic photochemistry: time-resolved spectra of adsorbed hydrocarbons

Abstract Time-resolved fluorescence spectra were measured for pyrene and naphthalene adsorbed on a silica gel surface using the time-correlated photon-counting technique Excimer-Iike emission was observed within an excitation lamp duration of a few nanoseconds with both pyrene and naphthalene. It is suggested, from the excitation spectra, that ground state complexes of the adsorbates are responsible for the formation of the excimer-like emission.