Naphthalene, second excited singlet

Fig. 8. The c axis polarized second singlet-singlet absorption of As naphthalene in a durene host crystal. The center of the 0-0 band is near 34,550 cm 1 and that of the a (9) addition is near 35,050 cm 1. The fine structure, as narrow as 1 cm"1 in some crystals, is attributed to interference between the second excited singlet state and vibrational additions to the first which have coupling symmetry. The isotopes 1,4, 5,8 — dt, 2,3, 6,7 — d4, and dg-naphthalene produce entirely different structures. For a given isotope, the major structural features change as the separation between the two excited singlets is varied by host-induced shifts, but remain rather similar for hosts that produce the same separation.

The polarized absorption spectrum of 1,6-naphthyridine-de in naphthalene at 4 K in the region of the first two excited singlet states is shown in Fig. 3. The lowest singlet system with origin at 28794 cm-1 has been assigned 1A" nn ) 83>. The origin of the second singlet system has not been identified but comparison with the naphthalene spectra and the nature of the 1,6-naphthyridine-de spectrum... 

As an illustration of the performance of TDDFT, we compare various density functionals and wave function methods for the first singlet excited states of naphthalene in Tables 4, 5, and 6. All calculations were performed using the aug-TZVP basis set, while the complete active space self-consistent field (SCF) with second-order perturbation theory (CASPT2) results from Ref. 200 were obtained in a smaller double-zeta valence basis set with some diffuse augmentation. The experimental results correspond to band maxima from gas-phase experiments however, the position of the band maximum does not necessarily coincide with the vertical excitation energy, especially if... 

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