STUDY OF VAN-DER-WAALS CLUSTERS OF ANTHRACENE BY LASER-INDUCED FLUORESCENCE IN A SUPERSONIC JET - EVIDENCE FOR 2 STRUCTURALLY DIFFERENT DIMERS

van der Waals clusters of anthracene produced by supersonic expansion have been studied by laser-induced fluorescence. The results provide e vidence for the formation of two structurally different dimers as well as higher clusters. The dispersed fluorescence from the higher cluste rs is remarkably similar to that of the ''stable dimer'' of anthracene in the condensed phase, suggesting that the species attributed to the ''stable dimer'' is actually microcrystals or aggregates rather than a dimer.