Resonance Raman spectra of copper-porphin

Abstract

Resonance Raman spectra of copper‐porphin in solution have been obtained using the tunable rhodamine 6G dye, Ar⁺, and HeCd lasers for excitation. Several bands show variation of intensity with excitation wavelength and many combination and overtone bands have been observed with 5145 Å excitation. Depolarization ratios for the two anomalously polarized bands [ρ_l > (3/4)] at 1322 and 1587 cm⁻¹ remain constant (∼45) with all the exciting wavelengths in the α and β absorption regions while some polarized bands show variation of their ρ_l values. It is shown that the rigorous molecular symmetry of Cu‐porphin in solution is D_4h. Symmetry species of the vibrational modes have been assigned.