Topic summary
Electron correlation
Extracted from the Wikipedia article Electronic correlation.
Atomic and molecular systems
Electron correlation is sometimes divided into dynamical and non-dynamical (static) correlation. Dynamical correlation is the correlation of the movement of electrons and is described under electron correlation dynamics and also with the configuration interaction (CI) method. Static correlation is important for molecules whose ground state is well described only with more than one (nearly) degenerate determinant. In this case the Hartree–Fock wavefunction (only one determinant) is qualitatively wrong. The multi-configurational self-consistent field (MCSCF) method takes account of this static correlation, but not dynamical correlation.