Exact and approximate forms of the kinetic energy functional T <inf>s</inf>[ρ] for molecules obtained via local-scaling transformations

Abstract:

By means of a constructive procedure based on local-scaling transformations, we have obtained the following exact form for the noninteractive kinetic energy functional of general molecular systems: T s[ρ] = Tw[ρ] + ∑I ∫ ΩI d3rIρ5/3(r I)[1 + rI · ▽rI 1n λ(r I)]-2/3 × [3 + rI · ▽ rI 1n λ(rI)]2[τNI(rI) + τNC(rI) + κNI(rI) + κNC(rI)], where λ(r) is the local-scaling transformation function, Tw[ρ] is the von Weiszäcker term and τNI(rI) and κNI(rI) are the radial and angular enhancement factors, respectively, within an atomic domain ΩI. The terms τ NC(rI) and τNC(r I) (where C stands for "complement of I") contain all contributions to the radial and angular enhancement factors within Ω I coming from the "tails" of functions centered on nuclei outside ΩI. Also, in the context of an "atoms-in-a- molecule" approach, we discuss the construction of approximations to the kinetic energy enhancement factors appearing in the previous expression for Ts[ρ].

Año de publicación:

2003

Keywords:

• DFT
• Local-scaling transformations
• Kinetic energy functional

Fuente:

scopus