EXCIMER FORMATION IN JET-COOLED VANDERWAALS CLUSTERS OF 1-CYANONAPHTHALENE AND 1-CYANO-4-METHYLNAPHTHALENE

The fluorescence excitation spectra of 1-cyanonaphthalene and 1-cyano-4-methylnaphthalene in jet expansion indicate the formation of van der Waals clusters of these compounds. The excitation of the cluster bands (n > 3-4) affords a large Stokes-shifted excimer fluorescence with decay times of 140-150 ns, while that of the dimer band gives only short wavelength resonance fluorescence. Similar excimer fluorescence was detected by excitation of the ground-state dimer in a low temperature (77 K) rigid solution of 3-methylpentane and also of polycrystalline samples of these compounds. © 1990.