SINGLE-SITE ELECTRONIC-SPECTRA OF FREE-BASE PORPHIN IN AN N-OCTANE CRYSTAL AT 5 K

The single site fluorescence and excitation spectra of free base porph in in an n-octane crystal at 5 K are reported. The vibrational frequen cies of the ground and excited stales (Q(x), Q(y) and B bands) have be en determined from the spectra. The Q, region is very similar to the p reviously reported results from supersonic jet expansion. However, the Q(y) region is quite different in the jet and mixed crystal; the crys tal spectrum exhibits extensive vibronic coupling. The Soret band show s little vibronic structure. (C) 1997 Elsevier Science B.V.