Left: The structure of triphenylene demonstrating its all-benzenoid character. The lengths of the carbon-carbon bonds are indicated in Å . The bond lengths within the benzenoid rings (as drawn) are shorter by about as compared to those between the benzenoid rings. Right: The next smallest of the all benzenoid PAHs.
(Top) Calculated vibronic spectrum of triphenylene. (Bottom) LIF spectrum of triphenylene.
Cartoon depictions of the and states of triphenylene. The potential energy curves are to scale and represent distortion of an atomic unit along , the Kekulé mode of the central ring, either side of equilibrium.
The dispersed fluorescence spectrum from . The LIF spectrum is reflected below to highlight the similarities in their structure.
Fluorescence decay from .
Frequencies and assignments of bands observed in the LIF spectrum of triphenylene (Fig. 2).
A comparison of the computationally determined ground state vibrational frequencies with the vibrational frequencies of the vibronic bands in this study. Excited state frequencies were obtained by stepping the normal mode and performing TDDFT calculations at each point. Since the band could not be observed, the frequency of mode 35 is fixed at , the value from Chojnacki et al.(Ref. 6). The assignment for the band is uncertain.
Parameters describing the modes as described in Sec. III for simulation of the LIF spectrum. The frequencies, , are given in , with the lower state frequencies being used in Eq. (4). Reduced masses, , are given in amu. Other parameters are given in a.u. The Franck-Condon factor for transitions is taken as with that of transitions taken as .
Assignment of bands observed in the dispersed fluorescence spectrum of triphenylene obtained by pumping .
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