Transitions triplet state energy correlation

TDDFT calculations results were consistent with the band shapes of the optical spectra of the parent complexes and are shown in Fig. 14. The calculated optical transitions are shown as bars under the experimental spectra and consist of MLLCT, ligand-to-ligand charge transfer transitions (LLCT), intraligand n - tt transitions (IL), and metal-complex delocalized-charge transfer transitions (MCDCT). Triplet state energies were also calculated based on a3 MLLCT state and correlated with experimental emission spectral results [53]. 

Fig. 65. Energy levels of the Na-molecule. To the left are shown the singlet states to the right the triplet states. The dotted lines refer to the states of the atoms after dissociation. Arrows indicate the observed radiative transitions, brackets the correlation of molecular to atomic states.

Combining these features suggests a potential energy surface like that of Figure 16.19. The S() and Si surfaces are arranged as in a typical forbidden reaction. There is an avoided crossing, and ultimately So correlates to S]. However, as we climb So, we first hit a crossing point with Ti. The transition to a triplet state occurs here, and we proceed on to T] of acetone. 

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