Momentum space atomic first-order density matrices and ‘‘exchange-only’’ correlation factors

The structure of the reduced first-order density matrices in momentum space and ``exchange-only'' correlation factors for a few closed-shell atomic systems has been systematically investigated. These quantities are studied within the Hartree-Fock as well as the nonlocal-density-approximation regime. The suitably averaged contours have been plotted and some significant features are brought out. These quantities are seen to bear a gross resemblance to their respective position-space counterparts.