Abstract
The correlation-state spectrum accompanying photoemission in atomic neon was calculated by several methods, using the sudden approximation and focusing on states that are approximately described by single-electron excitation of the form . All the calculations gave satisfactory energy values, but the predicted intensities differed widely. Multiconfiguration Hartree-Fock (MCHF) orbitals and orthogonalized MCHF orbitals gave intensities in poor agreement with experiment. A final-state configuration-interaction calculation gave accurate energies for seven correlation states, but when combined with a single-determinant initial state, yielded intensities low by about a factor of 2. Initial-state configuration interaction (ISCI), including double-electron excitation of the form , etc., brought the intensities of the -type states into agreement with experiment. It was thus shown that ISCI is of equal importance to final-state CI in determining correlation-peak intensities. Correlation-state (or "shakeup") spectra therefore contain unique information about electron correlation in the ground state.
- Received 11 December 1975
DOI:https://doi.org/10.1103/PhysRevA.13.1475
©1976 American Physical Society