PERTURBATION AND DENSITY-GRADIENT EXPANSIONS IN D-DIMENSIONS

Electron or hole inhomogeneous liquids in two dimensions are currently of considerable interest for condensed-matter studies. This has motivated the generalization of density matrix perturbative calculations based on plane waves, already made in three dimensions, to D dimensions. A similar generalization has been effected for the gradient expansion of the kinetic energy density. In two dimensions, the early work of Lennard-Jones and Woods on a model crystal of hydrocarbons is left largely intact by the inclusion of gradient corrections.