ON THE INTERSYSTEM CROSSING OF PENTACENE IN P-TERPHENYL

Applying methods developed for single molecule spectroscopy to small e nsembles, we have recorded high-resolution fluorescence-excitation spe ctra for pentacene in all substitutional sites of a p-terphenyl single crystal. The difference in intersystem crossing efficiency for pentac ene molecules in the various substitutional sites is discussed on the basis of these spectra and data from optically detected magnetic reson ance experiments.