Local and non-local spin density functional calculations of the correlation energy of atoms in molecules

Local (including self-correlation corrections) and non-local correlation energy functionals are used to calculate the correlation energy of atoms and diatomic molecules. The reliability of five schemes is tested for both correlation and dissociation energies. Recently developed spin-polarised correlation energy functionals incorporating gradient corrections are found to be generally superior for the properties examined. The theory of atoms in molecules is used to aid in the discussion of the trends in correlation and dissociation energies.