Short-Range Electron Correlations of CO₂ Molecule by First Principles T-Matrix Calculations

Abstract

In this paper, we obtain the double ionization energy spectra and the two-electron distribution functions from the first principles evaluating the ladder diagrams up to the infinite order (T-matrix) and discuss the short-range electron correlations. The T-matrix, which describes the multiple scattering between electrons (or holes), can accurately represent the short-range repulsive Coulomb interaction. The double ionization energy spectra calculated for the CO₂ molecule agree with the corresponding experiments very well. And the two-electron distribution function obtained from the T-matrix clearly shows “Coulomb hole” due to the avoidance of the antiparallel spin electrons confined in a small region.