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 $π1$ state interacts with the $π3−2π*$⁠, $π2−2π*$⁠, and $π2−1π3−1π*$ 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 $3b2$ and $5a1$ states with the shake-up states were remarkable for furan and pyrrole, while the $4b2$ state of thiophene had relatively large intensity.