On the conjoint gradient correction to the Hartree-Fock kinetic and exchange energy density functionals
- Universidad Autonoma Metropolitana-Iztapalapa (Mexico)
The kinetic and the exchange energy functionals are. expressed in the form T[{rho}] = C{sub TF} {integral} drp{sup 5/3}(r)f{sub T}(s) and K [{rho}] = C{sub D}{integral} drp{sup 4/3} (r)f{sub K} (s), where C{sub TF} = (3/10)(3{pi}{sup 2}){sup 2/3} and C{sub D} = -(3/4)(3/ {pi}){sup 1/3} are the Thomas-Fermi and the Dirac coefficients, respectively, and s = {vert_bar}{gradient}{rho}(r){vert_bar}/C{sub s}{rho}{sup 4/3} (r), with C{sub s} = 2(3{pi}{sup 2}){sup 1/1}. These expressions are used to perform a comparison of f{sub T}(s) and f{sub K}(s) in terms of their generalized gradient expansion approximations. It is shown that f{sub K}(s) {approx} f{sub T}(s) in the range characteristic of the interior regions of atoms and many solids and that the second-order gradient expansion of the kinetic energy provides a rather reasonable approximation to the generalized gradient expansion approximation of both the kinetic and the exchange energy functionals. 14 refs., 1 fig., 1 tab.
- OSTI ID:
- 482458
- Journal Information:
- International Journal of Quantum Chemistry, Vol. 57, Issue 1; Other Information: PBD: 5 Jan 1996
- Country of Publication:
- United States
- Language:
- English
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