Generalized gradient approximation adjusted to transition metals properties: Key roles of exchange and local spin density

Abstract

Perdew-Burke-Ernzerhof (PBE) and PBE adapted for solids (PBEsol) are exchangecorrelation (xc) functionals widely used in density functional theory simulations. Their differences are the exchange, μ, and correlation, β, coefficients, causing PBEsol to lose the Local Spin Density (LSD) response. Here, the μ/β two-dimensional (2D) accuracy landscape is analyzed between PBE and PBEsol xc functional limits for 27 transition metal (TM) bulks, as well as for 81 TM surfaces. Several properties are analyzed, including the shortest interatomic distances, cohesive energies, and bulk moduli for TM bulks, and surface relaxation degree, surface energies, and work functions for TM surfaces. The exploration, comparing the accuracy degree with respect experimental values, reveals that the found xc minimum, called VV, being a PBE variant, represents an improvement of 5% in mean absolute percentage error terms, whereas this improvement reaches 11% for VVsol, a xc resulting from the restoration of LSD response in PBEsol, and so regarded as its variant.

Concepts, models, and methods in computational heterogeneous catalysis illustrated throughCO2conversion

“…Note that the development of density functionals has systematically followed the best description of a particular property reducing the scope of them. Such strategy sacrifices universality by accuracy, although there have been efforts to develop new functionals describing a plethora of properties for families of systems, such as Vega‐Viñes (VV) for transition metals 123 . This is the reason why one finds density functionals that provide accurate descriptions for properties like the nuclear resonance chemical shift, 124 ionization potential, 125 formation energy, 126 or electronic band gap, 127 just to name a few.…”

“…In fact, GGA functionals win the balance between accuracy and computational efficiency against hybrid functionals. 123,141 A weak point of most DFT methods, including those of the LDA, GGA, meta-GGA, and hybrid families, is the neglect of the long-range electron interactions such as dispersion that govern non-covalent bonding interactions. This results in an inadequate and sometimes erroneous description of intermolecular or molecule-surface interactions.…”

“…However, hybrid functionals are computationally expensive, especially when plane wave basis sets are employed, and have difficulties in describing correctly metallic systems, two drawbacks that make them less appropriate for computational heterogenous catalysis. In fact, GGA functionals win the balance between accuracy and computational efficiency against hybrid functionals 123,141 …”

Identifying the Atomic Layer Stacking of Mo2C MXene by Probe Molecule Adsorption

“…Nevertheless, the PBE functional has proven to be among the most robust when describing the properties of bulk and surface transition metals. 31 − 33 Consequently, it has been broadly used in the computational heterogeneous catalysis field. 26 In addition, the adsorption and, more importantly, reactivity of molecules adsorbed at the MXene surfaces is well-described by PBE-D3 as shown in previous works.…”

Unravelling Morphological and Topological Energy Contributions of Metal Nanoparticles

“…Such calculations were performed employing density functional theory (DFT), the regular working horse when studying metal NPs, yielding accurate results at a reasonable computing time. For transition metals (TMs), generalised gradient approximation (GGA) exchange-correlation functionals such as the Perdew–Burke–Ernzerhof (PBE) [ 27 ] have been found to be among the best describing TMs bulk and surface properties [ 28 , 29 ]. However, as long as NP modelling is concerned, even if periodic surface models are extremely useful [ 28 ], a duly simulation requires the employment of well-shaped isolated NPs.…”