FRANCK-CONDON EFFECTS IN RESONANCE RAMAN-SPECTRA OF TCNQ- AND C10H8- A SEARCH FOR DUSHINSKY ROTATION OF TOTALLY SYMMETRICAL MODES( RADICALS)

The resonance Raman spectra of tetracyanoquinodimethane anion (TCNQ(-) )and naphthalene cation (C10H8+) are analyzed in terms of theoretical model based on the Franck-Condon effects. The models include also the effect of rotation of totally symmetric normal coordinates upon electr onic excitation to the resonant state (Dushinsky effects). It is shown that such a simple model accounts correctly for the available resonan ce Raman spectra for TCNQ(-) and C10H8+ radicals. The possible model r efinements such as vibronic coupling effects are also briefly discusse d.