Laser-induced fluorescence excitation spectrum of jet-cooled 4-(9-anthryl)aniline: observation of two weakly coupled electronic states

4-(9-Anthryl)aniline (AA), which forms a twisted intramolecular charge transfer state in a polar solvent, has been studied by using LIF excitation spectra under jet-cooled conditions. The vibrational structure of AA is analyzed as being composed of two kinds of progressions corresponding to the transitions to two weakly coupled electronic states. One is a so-called locally excited state and the other is a characteristic transition induced by the presence of the NH2 group. This uncommon observation is discussed in relation to the charge transfer state formation.