PICOSECOND RELAXATION OF CHARGE-TRANSFER STATES IN AN ASYMMETRIC CERIUM DOUBLE-DECKER SANDWICH COMPOUND

Subpicosecond time-resolved absorption studies have been carried out o n a cerium porphyrin-phthalocyanine sandwich mixed dimer in the liquid and solid states. Following excitation, two relaxation processes havi ng time constants of almost-equal-to 1 and almost-equal-to 40 ps are o bserved irrespective to the nature of the environment. The first proce ss is attributed to the relaxation of the excited state of the dimer t o a low-lying charge transfer state. The second one, much slower, acco unts for the relaxation of the charge transfer state back to the groun d state. The comparison of the liquid and solid phase data clearly all ows the role of the solvent in the relaxation processes to be eliminat ed.