Anthracene high vibrational energy

Based on a Huckel model for the anthracene fragments of BA (which is an even alternant hydrocarbon) one can show that the delocalized LE state and the CT states should all have the same 7t bond order. This in turn implies that the vibrational modes and frequencies should be similar for LE, CT, and CT. Thus the vibrations of bianthryl can be ignored in the energy dependence on z (even for highly polar solvents). 

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