Temperature-Dependent Magnetic Circular Dichroism of Lutetium Bisphthalocyanine

Abstract

Magnetic circular dichroism (MCD) and absorption spectra are reported for the Q, RV, and IV band regions (6000-19000 cm-1) of lutetium bisphthalocyanine in poly(methyl methacrylate) films and Ar matrixes. Weak, temperature-independent MCD of the IV band (∼7500 cm-1) is consistent with its assignment to the intervalence transition of a delocalized mixed-valence system. The temperature-dependent MCD of the Q (∼15300 cm-1) and RV (∼11000 cm-1) bands is quantified by moment analysis and interpreted to indicate excited-state spin-orbit splittings due to weak mixing of metal and ligand π Orbitals. The spectra are semiquantitatively consistent with interpretation of these bands as arising from fully allowed transitions terminating in exciton coupling states derived principally from π* ← π excitations of the individual ligands. Show more