Determination of electronic chemical potential within density functional theory

Abstract

The Donnelly-Parr version of the density-matrix functional theory [R.A. Donnelly, R.G. Parr, J. Chem. Phys. 69 (1978) 4431] is tested with various approximate energy functionals being used. The results obtained are discussed in the context of the functional N-representability condition. It has been demonstrated that the Euler-Lagrange equation proposed by Donnelly and Parr has no solutions within the set of N-representable density matrices. It follows that the validity of Sanderson's Principle of Electronegativity Equalization is open to question. Techniques for evaluating the electronic chemical potential within density functional theory are briefly discussed. The approximation of the electronic chemical potential with the three-point finite-difference scheme seems to be the most relevant route to its evaluation at the present stage of development. (C) 2000 Elsevier Science B.V.