Detection of higher excited states of p-fluorotoluene with (3 + 1)RMPI spectra Original Research Article

In this paper the results of detection of higher excited states of p-fluorotoluene in the gas phase are presented. Within a laser scanning range of 547.0–570.0 nm (3+1) RMPI spectra are obtained, and some vibrational structures on the third electronically excited valence state are observed. According to the polarization characteristic of the multiphoton transition the symmetry of the electronic state is determined as A1+B1+3pB2. Correlated to excited states of benzene, the results show that A1+B1 corresponds to 1E1u and 3pB2 to 3p 1A2u. It indicates that the double degeneracy of 1E1u state does not yet degrade in p-fluorotoluene. Moreover, it occasionally degenerates with 3p1 A2u. Furthermore, the electron distribution in the phenyl ring maintains the symmetry of the D6h point group consistently like in benzene.