A graphical unitary group approach to study multiplet specific multichannel electron correlation effects in the photoionization of O 2 Academic Article uri icon


  • We have implemented an efficient multichannel configuration-interaction complete-active-space (MCCI-CAS) approximation to study electron-correlation effects in molecular photoionization. This approach is based on the graphical unitary group approach (GUGA) for computing matrix elements of the Hamiltonian and includes target relaxation, correlation, and polarization as well as correlation due to coupling between different asymptotic scattering channels. The statistical rule, which partitions the total cross section into multiplets by simple spin statistics, is easily derived in this formalism. The scattering equations are solved using the Schwinger variational method. We present multiplet specific results of a detailed MCCI-CAS Schwinger study of the photoionization of molecular oxygen in the photon energy region of 12.3-20.4 eV, including up to four coupled electronic channels. Our results show the importance of using correlated target states. We have obtained all of the autoionization structure near threshold that has been assigned experimentally. In addition, we predict structure not yet resolved by experiment. © 1995 American Institute of Physics.

author list (cited authors)

  • Stratmann, R. E., & Lucchese, R. R.

citation count

  • 82

publication date

  • June 1995