Reassignment of the electronic states of the trans dimer of acenaphthylene

Abstract

The fluorescence and excitation spectra of trans dimer of acenaphthylene in a shpol'skii matrix at 4K are reported. The spectra at 4k are compared with the fluorescence and excitation spectra at 77K, previously reported by us. A reassignment of the origin of the two electronic states is required by such a comparison. The comparison once again establishes the point that the g state is below the u state, as was originally found from the comparison of two-photon and one-photon spectra. However, the splitting, which was originally described as "exciton splitting" should actually be ascribed to "site splitting". The "exciton splitting", as given in the present study, is about 130 cm^-1.