Kohn-Sham density

In the preceding paragraph we have given a detailed survey of the Kohn-Sham approach to density functional theory. Now, we need to discuss some of the relevant properties pertaining to this scheme and how we have to interpret the various quantities it produces. We also will mention some areas connected to Kohn-Sham density functional theory which are still problematic. Before we enter this discussion the reader should be reminded to differentiate carefully between results that apply to the hypothetical situation in which the exact functional ExC and the corresponding potential Vxc are known and the real world in which we have to use approximations to these quantities. 

Are there any remedies in sight within approximate Kohn-Sham density functional theory to get correct energies connected with physically reasonable densities, i. e., without having to use wrong, that is symmetry broken, densities In many cases the answer is indeed yes. But before we consider the answer further, we should point out that the question only needs to be asked in the context of the approximate functionals for degenerate states and related problems outlined above, an exact density functional in principle also exists. The real-life solution is to employ the non-interacting ensemble-Vs representable densities p intro-... 

Grimme, S., Waletzke, M., 1999, A Combination of Kohn-Sham Density Functional Theory and Multi-Reference Configuration Interaction Methods , J. Chem. Phys., Ill, 5645. 

Pople JA, Gill PMW, Johnson BG (1992) Kohn-Sham density-functional theory within a finite basis set. Chem Phys Lett 199 557... 

Bickelhaupt FM, Baerends EJ (2000) Kohn-sham density functional theory predicting and understanding chemistry. In Lipkowitz KB Boyd DB (eds) Reviews in computational chemistry, vol. 15. Wiley-VCH, New York, pp 1-86... 

In molecular transport junctions, the Hamiltonian models are usually based on Kohn-Sham density functional theory [46—48]. They use relatively small basis sets because the calculations are sufficiently complicated, they take a number of empirical steps for dealing with the basis sets and their potential integrals, and they... 

In a molecular-orbital-type (Hartree-Fock or Kohn-Sham density-functional) treatment of a three-dimensional atomic system, the field-free eigenfunctions ir e can be rigorously separated into radial (r) and angular (9) components, governed by respective quantum numbers n and l. In accordance with Sturm-Liouville theory, each increase of n (for... 

F. Matthias Bickelhaupt and Evert Jan Baerends, Kohn-Sham Density Functional Theory Predicting and Understanding Chemistry. 

It seems fair to say that one of the consequences of the evolution and success of Kohn-Sham density functional methodology has been a diminished role for semi-empirical procedures (AMI, PM3, INDO etc.). While these can still be very useful, the capability of DFT to treat relatively large systems, and at an overall higher level of accuracy, has led to its being the method of choice in cases that earlier would have been treated semi-empirically. 

Over the past decade, Kohn-Sham density functional theory (DFT) has evolved into what is now one of the major approaches in quantum chemistry.1-20 It is routinely applied to various problems concerning, among other matters, chemical structure and reactivity in such diverse fields as organic, organometallic, and inorganic chemistry, covering the gas and condensed phases as well as the solid state. What is it that makes Kohn-Sham DFT so attractive Certainly, an important reason is that it represents a first-principles... 

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