Core-valence electron correlation effects in photodetachment ofCa−ions

Abstract

The R-matrix method has been used to perform a five-state (S-P-D-D-P) close-coupling calculation on the photodetachment of Ca ions with photon energies from threshold to 4 eV. Calculations both with and without the core-valence electron correlation are carried out. The dominant core-valence electron correlation is included by exciting one 3p electron to the valence orbitals. It has been found that the so-called core-valence correlation is quite crucial to the prediction of the position of the Cooper minimum and the distinct behavior of the photodetachment cross sections near P and P thresholds. The core-valence correlated calculation results in a Cooper minimum at 1.20 eV and a narrow shape resonance just above the 4s4p P threshold. These structures are in good agreement with experimental observations. The present result also supports the previous conclusion that core-valence electron correlation is responsible for reducing the electron affinity of valence-only results to much closer to the experiment.