ELECTRON-DENSITIES FROM THE BRUECKNER DOUBLES METHOD

The concept of the Brueckner orbital is examined, following a resurgen ce of interest in wavefunctions constructed from them. The distinction between Self Consistent Field, Natural and Brueckner orbitals are dis cussed. Total electron densities are calculated for several examples, and correlation densities are studied. It is found that the Brueckner orbitals are more localised than SCF orbitals. The total electron dens ity constructed from the Brueckner reference determinant with Brueckne r orbitals gives qualitatively similar pictures as other correlated me thods. Brueckner orbitals are found to show dissociation well.