THE ELECTRONIC-SPECTRUM OF FURAN

The 30 lowest electronic states of furan have been investigated with t heoretical calculations (up to approximately 8.3 eV), and the experime ntal spectrum scrutinized in the relevant energy region. Electron corr elation effects have been examined by performing calculations in a hie rarchy of coupled cluster models, and basis set effects have been inve stigated by carrying out calculations using extensive basis sets. The difference between vertical and adiabatic excitation energies have bee n calculated. Oscillator strengths, excited-state dipole moments, and second moments of the electronic charge distributions have been used t o characterize the calculated electronic transitions and final states. Several reassignments of features in the experimental spectrum have b een suggested.