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Other version: http://link.aps.org/doi/10.1103/PhysRevA.85.032518
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Purestate noninteracting vrepresentability of electron densities from KohnSham calculations with finite basis sets 

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Published in  Physical Review. A. 2012, vol. 85, no. 3, p. 032518/19  
Abstract  Within the linear combination of atomic orbitals (LCAO) approximation, one can distinguish two different KohnSham potentials. One is the potential available numerically in calculations, and the other is the exact potential corresponding to the LCAO density. The latter is usually not available, but can be obtained from the total density by a numerical inversion procedure or, as is done here, analytically using only one LCAO KohnSham orbital. In the complete basisset limit, the lowestlying KohnSham orbital suffices to perform the analytical inversion, and the two potentials differ by no more than a constant. The relation between these two potentials is investigated here for diatomic molecules and several atomic basis sets of increasing size and quality. The differences between the two potentials are usually qualitative (wrong behavior at nuclear cusps and far from the molecule even if Slatertype orbitals are used) and δlike features at nodal planes of the lowestlying LCAO KohnSham orbital. Such nodes occur frequently in LCAO calculations and are not physical. Whereas the behavior of the potential can be systematically improved locally by the increase of the basis sets, the occurrence of nodes is not correlated with the size of the basis set. The presence of nodes in the lowestlying LCAO orbital can be used to monitor whether the effective potential in LCAO KohnSham equations can be interpreted as the potential needed for purestate noninteracting vrepresentability of the LCAO density. Squares of such nodecontaining lowestlying LCAO KohnSham orbitals are nontrivial examples of twoelectron densities which are not purestate noninteracting vrepresentable.  
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Research group  Groupe Wesolowski  
Citation (ISO format)  DE SILVA, Piotr, WESOLOWSKI, Tomasz Adam. Purestate noninteracting vrepresentability of electron densities from KohnSham calculations with finite basis sets. In: Physical Review. A, 2012, vol. 85, n° 3, p. 032518/19. https://archiveouverte.unige.ch/unige:21865 