Depolarization Dispersion of Totally Symmetric Fundamentals in Resonance Raman Spectra. Analysis for Azobenzene Dyes

P. Sassi and M. Pawlikowski Department of Theoretical Chemistry, Jagiellonian University, Faculty of Chemistry, Ingardena 3, 30-060 Kraków, Poland

Received: February 6, 1996; revised version: May 8, 1996

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The resonance Raman excitation profiles and depolarization dispersions for totally symmetric vibrations are studied under the energy region corresponding to an excitation of two low-energy states of 4-nitro-4'-diethylaminoazobenzene dye. In a contrast to the earlier analysis of this dye we assume that the low-energy states of the molecule studied have different polarizations. It results in the depolarization dispersions of the Raman lines of totally symmetric vibrations. The effect is illustrated for two vibrations: ν4=1342 cm-1 and ν7=1448 cm-1 for which excitation profiles show distinctive intensity distribution patterns due to interferences between the vibrational manifolds of the overlapping states. The nature of the electronic (resonant) states and the magnitudes of Franck-Condon parameters determined from the experiment are also briefly discussed.

DOI: 10.12693/APhysPolA.90.509 PACS numbers: 33.20.Fb