7i-7t* transitions

For 7i - 7t" transitions of aromatic hydrocarbons, the absorption transition moments are in the plane of the molecule. The direction with respect to the molecular axis depends on the electronic state attained on excitation. For example, in naphthalene and anthracene, the transition moment is oriented along the short axis for the So —> Si transition and along the long axis for the So —> S2 transition. Various examples are shown in Figure 2.3. 

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