PLATINUM PHTHALOCYANINE SYMMETRY AND SINGLET-TRIPLET ENERGY-TRANSFER FROM ELECTRONIC AND VIBRONIC SHPOLSKII SPECTRA

We report the first experimental study and detailed analysis of the structures in the phosphorescence, phosphorescence excitation, absorption, and resonance Raman spectra of platinum phthalocyanine (PtPc) in Shpol'skii matrices consisting of alphachloronapthalene (α-CIN) and n-octane. The studies were done at temperatures down to 1.5 K. From the data reported we arrive at a number of new observations, the principal ones being: (1) The confirmation that the molecular symmetry of PtPc in the ground as well as in the excited singlet and triplet states is less than D4h. (2) The identification of two additional radiative electronic triplet states at energies lower than the previously reported ones, as well as an additional excited electronic singlet state. (3) Information on splittings, vibronic transitions, intersystem crossing mechanisms, solvent and site effects, and potential surfaces, some of it in considerable detail. © 1979.