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Keywords:

  • density functional theory;
  • power series with correct density scaling;
  • one-electron density;
  • ground state total electronic energy

Abstract

The reduction of the electronic Schrodinger equation or its calculating algorithm from 4N-dimensions to a nonlinear, approximate density functional of a three spatial dimension one-electron density for an N electron system which is tractable in practice, is a long-desired goal in electronic structure calculation. In a seminal work, Parr et al. (Phys. Rev. A 1997, 55, 1792) suggested a well behaving density functional in power series with respect to density scaling within the orbital-free framework for kinetic and repulsion energy of electrons. The updated literature on this subject is listed, reviewed, and summarized. Using this series with some modifications, a good density functional approximation is analyzed and solved via the Lagrange multiplier device. (We call the attention that the introduction of a Lagrangian multiplier to ensure normalization is a new element in this part of the related, general theory.) Its relation to Hartree–Fock (HF) and Kohn–Sham (KS) formalism is also analyzed for the goal to replace all the analytical Gaussian based two and four center integrals (∫gi(r1)gk(r2)rmath imagedr1dr2, etc.) to estimate electron-electron interactions with cheaper numerical integration. The KS method needs the numerical integration anyway for correlation estimation. © 2012 Wiley Periodicals, Inc.