Electronic energy levels of benzene below 7 eV

Abstract

The electronic energy levels of benzene below 7 eV have been investigated in an electron impact experiment. Vibrational structure has been resolved for the first three singlet–triplet transitions and the second triplet state has been separated from the overlapping first singlet state. Energies of the vibrational bands of the observed singlet–triplet transitions are (strongest band underlined) S0→T1, 3.67, 3.79, 3.89, 3.98 eV; S0→T2, 4.63, 4.73, 4.85, 4.95 eV; S0→T3, 5.58, 5.69, 5.81 eV. The previous result of Lassettre et al. [E. N. Lassettre, A. Skerbele, M. Dillon, and K. Ross, J. Chem. Phys. 48, 5066 (1968)] which suggested that two electronic states are involved in the 6.2 eV region scattering has been confirmed. These results together with ultraviolet absorption data allow the construction of a rather detailed energy level diagram for benzene up to 7 eV.