STRUCTURAL MEASUREMENTS OF PERYLENE CLUSTERS WITH CYCLOPROPANE VIA ROTATIONAL COHERENCE SPECTROSCOPY

Rotational coherence experiments using picosecond time-correlated sing le-photon counting spectroscopy have measured the polarized fluorescen ce time profiles of van der Waals aggregates of perylene with up to th ree cyclopropane molecules. Three structural isomers have been confirm ed at the 2:1 level of aggregation, one of which contains a contacted cyclopropane dimer. The other two are symmetrically distinct isomers o f a (1\1) species. The 3:1 aggregate also exhibits two resolvable stru ctures. The structures of all complexes studied are shown to be genera ted by the off-center adsorption site of the cyclopropane molecule, ev idently dictated by short-range repulsive forces.