Search

The central role of the shape function σ(r_) from the density functional theory (DFT), the ratio of the electron density ρ(r_) and the number of electrons N of the system (density per particle), is investigated. Moreover, its relationship with DFT based reactivity indices is established. In the first part, it is shown that an estimate for the chemical hardness can be obtained from the long range behavior of the shape function and its derivative with respect to the number of electrons at a fixed external potential. Next, the energy of the system is minimized with the constraint that the shape function should integrate to unity; the associated Lagrange multiplier is shown to be related to the electronic chemical potential μ of the system. Finally, the importance of the shape function for both molecular structure, reactivity, and similarity is outlined. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We report the results of numerical tests on atom He-Lu, which suggest that the exchange energy calculated within the spin-polarized exchange-only optimized potential model for atoms can be expressed as a power-law in terms of the local effective exchange potential evaluated at the nucleus. The total effective exchange potential increases linearly with the atomic number. These results are useful in improving the energy density functionals at the small r region where most of the popularly used energy functionals provide rather poor functional derivatives. The significance of the present results in obtaining detailed information on the correlation-kinetic energy of the Kohn-Sham model is discussed. [ABSTRACT FROM AUTHOR]

Using classical electrostatics, the total effective integrated charge-density function is calculated for Be and Ne using the multiplicative potentials derived from (1) Hartree and (2) Hartree–Fock approximation to quantal density functional theory (3)exchange-only optimized effective potential and (4) Kohn–Sham exchange-correlation potential using the quantum Monte Carlo density. The evolution of effective integrated charge-density function for these atoms is examined as the electron correlation is built up stepwise from its absence to the stage of its near complete presence. These results provide a deeper understanding of the Kohn–Sham exchange-correlation potential in terms the correspondingly defined integrated charge-density functions based on the Poisson equation. [ABSTRACT FROM AUTHOR]

Using the static exchange‐correlation charge density concept, the total integrated exchange‐charge density function is calculated within the nonrelativistic spin‐restricted exchange‐only (i) optimized effective potential model, and (ii) nonvariational local potential derived from the exchange‐only work potential within the quantal density functional theory, for the ground‐state isoelectronic series: Ga+, Zn, Cu−; In+, Cd, Ag−; and Tl+, Hg, Au−. The difference between the exchange charge density function derived from these potentials is employed to evaluate the first‐order correlation‐kinetic contribution to the integrated exchange charge density. This contribution is found to be important for both the intra‐ and inter‐shell regions. Screening effects on the contribution due to the nd10 (n = 3–5) subshells are discussed through comparisons with similar calculations on Ca, Sr, and Ba, wherein nd10 electrons are absent. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 [ABSTRACT FROM AUTHOR]

The radii and electrostatic potential of singly-negative ions of the 3d,4d and 5d transition series have bee calculated. This gives a quantitative estimate of the size of these ions.(AIP) [ABSTRACT FROM AUTHOR]