Fluorescence of Pyrene Aggregates Formed in a Supersonic Jet

摘要

The excitation and fluorescence spectra and fluorescence decay time of aggregates of pyrene molecules that are formed upon cooling in a supersonic jet are measured. The fluorescence spectrum excited by short-wavelength radiation exhibits a long-wavelength band, which is different from the fluorescence band of pyrene molecules and is assigned to pyrene excimers. It is shown that, in a supersonic jet, in contrast to the known mechanism of formation of excimers, at first, Van der Waals complexes are formed in the ground state, which transfer upon laser irradiation to the excited vibronic state of the excimer.