ELECTRONIC SPECTROSCOPY OF 1,3-CYCLOPENTADIENE, 1,3-CYCLOHEXADIENE AND 1,3-CYCLOHEPTADIENE BY ELECTRON-IMPACT

The electronic spectra of three conjugated cis-dienyl systems, 1,3-cyclopentadiene, 1,3-cyclohexadiene, and 1,3-cycloheptadiene have been investigated using electron-impact spectroscopy. Spectra were obtained at impact energies ranging from 20 to 75 eV and scattering angles from 5° to 80°. A single singlet → triplet transition was observed for each molecule at 3.10, 2.94, and 2.99 eV, respectively. Information on the Franck-Condon envelopes was obtained for these transitions. The N→V1, N→V2 and V3, and several Rydberg transitions were also observed in each substance. Some previously unreported superexcited states lying above the first ionization potential were detected. © 1979 American Institute of Physics.