Vibronic interactions naphthalene

Benchmark ab initio quantum dynamical studies are carried out for the prototypical naphthalene and anthracene radical cations of the PAH family aiming to understand the vibronic interactions and ultrafast decay of their low-lying electronic states. The broadening of vibronic bands and ultrafast internal conversion through conical intersections in the Da — — D2 electronic states of these species is... 

In triplet transitions, the resonance interaction and thus the Davydov splitting can, as mentioned, no longer be understood in terms of a dipole interaction, but rather as an exchange betv een orbitals which overlap. Measured values are available only for Ti states. Figure 6.10 shows as an example, similar to Fig. 6.1, the two 0,0 components of the excitation spectrum Ti So, of the triplet exciton Ti in an anthracene crystal here, however, the spectrum was taken at 1.8 K. 0,0 transition means that the excitation affects only excitons and that no additional phonons or vibrons are excited. In anthracene, the Davydov splitting of the Ti excitonic state is 21.5 cm" (cf Fig. 6.10). In naphthalene, it is 9.8 cm [34]. 

In the following we want, therefore, to describe first the structure of the simplest organic metal derived from as simple molecules as naphthalene or other arenes. These structures help to understand the type of intermolecular interactions necessary to produce a quasi-metallic state in organic systems. The structure and the structural changes upon oxidation ("doping") of poly(acetylene) will then be described. A description of these chemical reactions and their implications for the electronic and vibronic spectra will follow. Finally, some other conducting polymers or oligomers will be described and the use of such materials in electrochemical cells will be discussed as well. 

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