Journal of Chemical Physics, Vol.101, No.9, 7364-7371, 1994
Fluorescence and Hole-Burning Depletion Spectra of 1-(9-Anthryl)-3-Phenylpropane and 1-(1-Anthryl)-3-Phenylpropane in Supersonic Free Jet
Fluorescence excitation and hole burning depletion spectra of 1-(1- and 9-anthryl)-3-phenylpropanes (1- and 9-An-Ph) in a supersonic free jet suggest two types of ground state conformers, which are dependent on the cooling conditions of supersonic expansion. The two major conformers were ascribed to trans/trans (t/t) and gauche/trans (g/t) concerning the torsional conformations of C-1-C-2 and C-2-C-3 bondings. In addition to the tit conformation of 1-An-Ph, the anti-gauche/trans (anti-g/t) conformer was proposed to be most plausible. The t/t and g/t (anti-g/t) conformers exhibit different fluorescence decay times. The former (t/t) of both compounds shows excess vibrational energy dependence of decay times as well as dispersed spectra, while decay times of the latter g/t and anti-g/t are less dependent. The optimum geometries of these conformations in the ground state were obtained by the AM-1 calculation. The different fluorescent features of these conformations were discussed in terms of the intramolecular vibrational energy redistribution in geometrically restricted conformations of the g/t (9-An-Ph) and anti-g/t (1-An-Ph).
Keywords:VIBRATIONAL-RELAXATION;COOLED ALKYLBENZENES;CLUSTERS;SPECTROSCOPY;1-CYANONAPHTHALENE;PHOTOELECTRON;EXCITATION;DEPENDENCE;MOLECULES;PERYLENE