Category:GGA: Difference between revisions
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GGA exchange-correlation functionals depend on the electron density <math>\rho</math> and its first derivative <math>\nabla\rho</math>: | GGA exchange-correlation functionals depend on the electron density <math>\rho</math> and its first derivative <math>\nabla\rho</math>: | ||
:<math>E_{\mathrm{xc}}^{\mathrm{GGA}}=\int\epsilon_{\mathrm{xc}}^{\mathrm{GGA}}(\rho,\nabla\rho)d^{3}r</math> | :<math>E_{\mathrm{xc}}^{\mathrm{GGA}}=\int\epsilon_{\mathrm{xc}}^{\mathrm{GGA}}(\rho,\nabla\rho)d^{3}r</math> | ||
Among the various types of functionals, the GGAs, along with LDA, are the fastest to evaluate | Among the various types of functionals, the GGAs, along with LDA, are the fastest to evaluate, therefore particularly useful for very large systems. They are very often sufficiently accurate for the geometry optimization or the cohesive energy, but less recommended for properties related to the electronic band structure like the band gap. The GGA that has been the most commonly used in solid-state physics is PBE{{cite|perdew:prl:1996}}. | ||
== How to == | == How to == |
Revision as of 12:20, 19 January 2022
Theoretical Background
GGA exchange-correlation functionals depend on the electron density and its first derivative :
Among the various types of functionals, the GGAs, along with LDA, are the fastest to evaluate, therefore particularly useful for very large systems. They are very often sufficiently accurate for the geometry optimization or the cohesive energy, but less recommended for properties related to the electronic band structure like the band gap. The GGA that has been the most commonly used in solid-state physics is PBE[1].
How to
A GGA can be used by specifying the tag GGA in the INCAR file.