RESONANCE RAMAN-STUDY OF FRANCK-CONDON EFFECTS IN THE C10H8- AB-INITIO MCSCF CALCULATIONS FOR THE LOW-ENERGY B-2(2G) AND B-2(3G) SYMMETRY STATES( RADICAL )

Resonance Raman spectra in the region corresponding to the (2)A(u)(D-0 ) --> 1(2)B(3g)(D-2) electronic excitation of the naphthalene cation ( C10H8+) are studied in terms of a model based on Franck-Condon (FC) ef fects. This simple model correctly accounts for the RRS spectra and yi elds FC parameters which correspond to those obtained from ab initio M CSCF computations. Computed FC activities of nine totally symmetric mo des in the B-2(3g)(D-2) and (B2gD4)-B-2) states of the C10H8+ radical are discussed and compared to experiment and earlier theoretical studi es based on the ROHF/3-21G approach.