The near-IR, visible and UV regions of the absorption spectrum of naphthalene anion (C_{10}H_{8}^{–}) are studied in terms of full optimized reaction space multiconfiguration self-consistent field method applied with Dunning's double-zeta basis set including polarization and diffuse functions on the all hydrogen atoms. Computed Franck-Condon activity of the all (nine) totally symmetric vibrations in the seven low-energy transitions is discussed and compared to the available experimental data. The assignment for some electronic transitions in the visible part of the naphthalene anion absorption spectrum is corrected on the base of full optimized reaction space multiconfiguration self-consistent field computations. We have argued that two (overlapping) bands at 21700 cm^{-1} and 26800 cm^{-1} are due to 1^{2}B_{1g} → 1^{2}A_{u} and 1^{2}B_{1g} → 2^{2}A_{u} transitions rather than to the short-axis and long-axis polarized ones as was suggested in an earlier semiempirical treatment. An experimental method appropriate to verify this result is proposed.
A_{1}/D_{0} and D_{0} characteristics of magnetic circular dichroism and absorption spectra are studied for the low-energy A_{g} → T_{1u} transitions in the C_{60} molecule in terms of the self-consistent field Parieser-Parr-Pople method applied in the full configuration interaction-1 treatment. The effects are discussed at different levels of configuration interaction and the results are compared to the earlier ones obtained From the CNDO/S method. We argue that the earlier treatment fails to account correctly for the experimental magnetic circular dichroism and absorption spectra of C_{60} molecule. This is most probably due to deficiency of the configuration interaction basis set and/or to the intrinsic parametrization of complete neglect of differential overlap method.
Chiral properties of peridinin-chlorophyll-protein (PCP) light-harvesting complexes are studied in terms of vibronic dimer theory previously applied to study certain structural aspects of α-crustacyanin pigments. On the base of CD spectra it is shown that the peridinin dimer acts as a chiral group in PCP complexes and its geometrical structure is such that the peridinin monomers cannot be coplanar. Certain observations concerning the energy transfer process in PCP complexes in vivo are also made.
The resonance Raman spectra of tetracyanoquinodimethane anion (TCNQ^{-}) and naphthalene cation (C_{10}H^{+8}) are analyzed in terms of theoretical model based on the Franck-Condon effects. The model includes also the effect of rotation of totally symmetric normal coordinates upon electronic excitation to the resonant state (Dushinsky effects). It is shown that such a simple model accounts correctly for the available resonance Raman spectra for TCNQ^{-} and C_{10}H^{+8} radicals. The possible model refinements such as vibronic coupling effects are also briefly discussed.
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: ν_{4}=1342 cm^{-1} and ν_{7}=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.
Model calculations are reported for an (E+E)∗e system including linear and quadratic Jahn-Teller and Herzberg-Teller vibronic interactions. The effects of these interactions on magnetic circular dichroism and absorption spectra are compared with experimental observations on CoF^{3-}_{6} salts.
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