Popular modern generalized gradient approximations are biased toward the description of free-atom energies. Restoration first-principles expansion for exchange over a wide range density gradients eliminates this bias. We introduce revised Perdew-Burke-Ernzerhof approximation that improves equilibrium properties densely packed solids and their surfaces.

Semilocal density functionals for the exchange-correlation energy are needed large electronic systems. The Tao-Perdew-Staroverov-Scuseria (TPSS) meta-generalized gradient approximation (meta-GGA) is semilocal and usefully accurate, but predicts too-long lattice constants. Recent "GGA's solids" yield good constants poor atomization energies of molecules. We show that construction principle one them (restoring expansion exchange over a wide range densities) can be used to construct "revised...

Some fundamental issues in ground-state density functional theory are discussed without equations: (1) The standard Hohenberg-Kohn and Kohn-Sham theorems were proven for a Hamiltonian that is not quite exact real atoms, molecules, solids. (2) the exchange-correlation energy, which must be approximated, arises from tendency of electrons to avoid one another as they move through electron density. (3) In absence magnetic field, either spin densities or total can used, although former choice...

We construct a Laplacian-level meta-generalized gradient approximation (meta-GGA) for the non-interacting (Kohn-Sham orbital) positive kinetic energy density $\tau$ of an electronic ground state $n$. This meta-GGA is designed to recover fourth-order expansion $\tau^{GE4}$ in appropiate slowly-varying limit and von Weizs\"{a}cker expression $\tau^{W}=|\nabla n|^2/(8n)$ rapidly-varying limit. It constrained satisfy rigorous lower bound $\tau^{W}(\mathbf{r})\leq\tau(\mathbf{r})$. Our typically...

We use the asymptotic expansions of semiclassical neutral atom as a reference system in density functional theory to construct accurate generalized gradient approximations (GGAs) for exchange-correlation and kinetic energies without any empiricism. These functionals are among most GGAs molecular systems, perform well solid state, overcome current GGA state art frozen embedding calculations. Our results also provide evidence conjointness conjecture between exchange atomic systems.

We present a new class of noninteracting kinetic energy (KE) functionals, derived from the semiclassical-atom theory. These functionals are constructed using link between exchange and energies employ generalized gradient approximation (GGA) for enhancement factor, namely, Perdew-Burke-Ernzerhof (PBE) one. Two them, named APBEK revAPBEK, recover in slowly varying density limit modified second-order (MGE2) expansion KE, which is valid neutral atom with large number electrons. contains no...

Abstract We present the theory of semilocal exchange‐correlation (XC) energy functionals which depend on Kohn–Sham kinetic density (KED), including relevant class meta‐generalized gradient approximation (meta‐GGA) functionals. Thanks to KED ingredient, meta‐GGA can satisfy different exact constraints for XC and be made one‐electron self‐correlation free. This leads a better accuracy over wider range properties with respect GGAs, often reaching hybrid functionals, but at much reduced...

Kinetic energy (KE) approximations are key elements in orbital-free density functional theory. To date, the use of nonlocal functionals, possibly employing system-dependent parameters, has been considered mandatory order to obtain satisfactory accuracy for different solid-state systems, whereas semilocal generally regarded as unfit this aim. Here, we show that, instead, properly constructed approximations, Pauli-Gaussian (PG) KE especially at Laplacian level theory, can indeed achieve...

We test Laplacian-level meta-generalized gradient approximation (meta-GGA) non-interacting kinetic energy functionals based on the fourth-order expansion (GE4). consider several well known meta-GGAs from literature (bare GE4, modified and MGGA functional of Perdew Constantin [Phys. Rev. B \textbf{75},155109 (2007)]), as two newly designed (named L0.4 L0.6). First, a general assessment different is performed, testing them for model systems (one-electron densities, Hooke's atom jellium...

We study the compatibility between PBEsol exchange-correlation energy functional of Phys. Rev. Lett. 100, 136406 (2008) and rVV10 van der Waals nonlocal correlation B 87, 041108 (2013). By applying a density-gradient dependence in expression rVV10, we develop new functional: The + rVV10s functional, which is remarkably accurate for layered solids, rare-gas crystals, densely packed bulk adsorption noble-gas atoms on metal surfaces, also competitive noncovalent interactions molecular complexes...

We present a Thomas-Fermi-inspired density scaling under which electron densities of atomic, molecular, or condensed matter become both large and slowly varying, so that semiclassical approximations second-order gradient expansions are asymptotically exact for the kinetic exchange energies. Thus, even atoms molecules, density-functional should recover universal in this limit. also explain why common generalized do not.

We propose a generalized gradient approximation (GGA) for the angle- and system-averaged exchange-correlation hole of many-electron system. This hole, which satisfies known exact constraints, recovers Perdew-Burke-Ernzerhof solids (PBEsol) energy functional, GGA that accurately describes equilibrium properties densely packed their surfaces. find our PBEsol wave-vector analysis jellium surface in agreement with sophisticated time-dependent density-functional calculation (whose...

We study the asymptotic expansion of neutral-atom energy as atomic number Z-->infinity, presenting a new method to extract coefficients from oscillating numerical data. Recovery correct yields condition on Kohn-Sham kinetic that is important for accuracy approximate functionals atoms, molecules, and solids. For example, this determines small gradient limit any generalized approximation conflicts somewhat with standard expansion. Tests are performed jellium clusters using densities...

Within the framework of ab initio time-dependent density-functional theory (TD-DFT), we propose a static approximation to exchange-correlation kernel based on jellium-with-gap model. This accounts for electron-hole interactions and it is able address both strongly bound excitons weak excitonic effects. TD-DFT absorption spectra several bulk materials (both semiconductor insulators) are reproduced in very good agreement with experiments low computational cost.

We construct a meta-generalized-gradient approximation which properly balances the nonlocality contributions to exchange and correlation at semilocal level. This non-empirical functional shows good accuracy for broad palette of properties (thermochemistry, structural properties) systems (molecules, metal clusters, surfaces bulk solids). The several well known problems in electronic structure calculations, such as bending potential silver trimer dimensional crossover anionic gold is also...

We construct a generalized gradient approximation of the exchange-correlation energy that satisfies nonuniform scaling in one dimension and is accurate whole quasi-two-dimensional (Q2D) regime. Using spatial energetic analyses metal (111) surfaces, we show Q2D behavior important at surface most transition metals, here proposed Q2D-generalized functional predicts for these metals energies as well bulk properties.

Using the semiclassical neutral atom theory, we extend to fourth order modified gradient expansion of exchange energy density functional theory. This can be applied both large atoms and solid-state problems. Moreover, show that it employed construct a simple non-empirical generalized approximation (GGA) exchange-correlation competitive with state-of-the-art GGAs for solids, but also reasonably accurate ordinary chemistry.

We show that the Kohn-Sham positive-definite kinetic energy (KE) density significantly differs from von Weizs\"acker (VW) one at nuclear cusp as well in asymptotic region. At cusp, VW functional is shown to be linear and contribution of p-type orbitals KE theoretically derived numerically demonstrated limit infinite charge, semiclassical neutral large atoms. In latter case, it reaches 12 density. region we find new exact constraints for meta Generalized Gradient Approximation (meta-GGA)...

The development of semilocal models for the kinetic energy density (KED) is an important topic in functional theory (DFT). This especially true subsystem DFT, where these are necessary to construct required non-additive embedding contributions. In particular, can also be efficiently employed replace exact KED meta-Generalized Gradient Approximation (meta-GGA) exchange-correlation functionals allowing extend DFT applicability meta-GGA level theory. Here, we present a two-dimensional scan as...

We assess several generalized gradient approximations (GGAs) and Laplacian-level meta-GGAs (LL-MGGA) kinetic energy (KE) functionals for orbital-free density functional theory calculations of bulk metals semiconductors, considering equilibrium distances, moduli, total energies, the electron densities. also considered effects pseudopotentials, vacancy formation bond lengths molecular dimers. found that LL-MGGA KE are distinctively superior to GGA functionals, showing importance Laplacian in...

We propose a model for the angle- and system-averaged exchange-correlation hole of many-electron system. This analyzes energy into contributions various distances $u$ from an electron. The is ``reverse-engineered'' (derived not used to derive density functional). It satisfies known exact constraints, including ones that can only be satisfied by meta-generalized gradient approximation or meta-GGA. incorporates Tao-Perdew-Staroverov-Scuseria (TPSS) nonempirical tested atoms applied jellium...

We resolve the long-standing controversy over metal surface energy: Density-functional methods that require uniform-electron-gas input agree with each other, but not high-level correlated calculations such as Fermi hypernetted chain and diffusion Monte Carlo predict uniform-gas correlation energy. Here we apply inhomogeneous Singwi-Tosi-Land-Sj\"olander method, find density functionals are indeed reliable (because energy is bulklike). Our work also vindicates use of uniform-gas-based...

We propose a generalized gradient approximation constructed for hybrid interfaces, which is based on the Perdew, Burke, Ernzerhof (PBE) functional form and interpolates between rapidly PBE slowly varying (PBEsol, revised solid-state systems) density regimes. This (named PBEint) recovers right second-order expansion of exchange energy accurate jellium surfaces, interacting slabs, molecules, solids, metal-molecule interfaces.