Electron-Impact Excitation Cross Sections of the Lowest-Lying Triplet States of Benzene

Abstract

Calculations of electron-impact excitation cross sections of the lowest-lying triplet states B1u3, E1u3, B2u3 of benzene are carried out, using the Ochkur and Ochkur–Rudge approximations. Electronic wavefunctions are constructed from the LCAO molecular orbitals for π electrons in benzene, and nuclear motions are disregarded. It is found that the differential cross section has a peak at a large scattering angle in the low-energy region. The angular distribution for the excitation of the B1u3, E1u3 states shows a broad subsidiary peak at a larger scattering angle. As the incident energy is lowered, the position of the peak in the angular distribution shifts towards larger scattering angles, and the subsidiary peak tends to vanish. The total excitation cross section for the lowest-lying triplet states is about πa02 at low incident energy. Results of calculations are discussed and compared with experimental findings.