Correlation Effects in Atoms

摘要: The applicability of many-body perturbation theory in calculating electron correlations atoms has been investigated. It was found that, order for results to agree well with experiment, certain classes diagrams, representing terms the series, must be included many orders. higher diagrams were more important among outer electrons than inner electrons. Methods summing various these found. total correlation energy beryllium calculated by theory, use an IBM 7090 computer, -2.48\ifmmode\pm\else\textpm\fi{}0.11 eV. value obtained from experiment is -2.59 energies different electronic shells -1.19 eV $2s$ electrons, -1.15 $1s$ and -0.135 between shells.