Electron correlation: The many-body problem at the heart of chemistry

Abstract: The physical interactions among electrons and nuclei, responsible for the chemistry of atoms and molecules, is well described by quantum mechanics and chemistry is therefore fully described by the solutions of the Schro¨dinger equation. In all but the simplest systems we must be content with approximate solutions, the principal difficulty being the treatment of the correlation between the motions of the many electrons, arising from their mutual repulsion. This article aims to provide a clear understanding of the physical concept of electron correlation and the modern methods used for its approximation. Using helium as a simple case study and beginning with an uncorrelated orbital picture of electronic motion, we first introduce Fermi correlation, arising from the symmetry requirements of the exact wave function, and then consider the Coulomb correlation arising from the mutual Coulomb repulsion between the electrons. Finally, we briefly discuss the general treatment of el...

• Type: Journal
• Year: 2007
• Where: JCC
• Authors: David P. Tew, Wim Klopper, Trygve Helgaker
• Keywords: Coulomb Correlation, Electron Correlation, Fermi Correlation, JCC 2007