Theoretical fine spectroscopy with symmetry-adapted-cluster configuration-interaction method: Outer- and inner-valence ionization spectra of furan, pyrrole, and thiophene

Theoretical fine spectroscopy has been performed for the valence ionization spectra of furan, pyrrole, and thiophene with the symmetry-adapted-cluster configuration-interaction general- R method. The present method described that the π 1 state interacts with the π 3 -2 π*, π 2 -2 π*, and π 2 -1 π 3 -1 π* shake-up states providing the split peaks and the outer-valence satellites, both of which are in agreement with the experiments. The intensity distributions were analyzed in detail for the inner-valence region. In particular, for furan, theoretical intensities were successfully compared with the intensity measured by the electron momentum spectroscopy. The interactions of the 3 b2 and 5 a1 states with the shake-up states were remarkable for furan and pyrrole, while the 4 b2 state of thiophene had relatively large intensity.