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Category:Exchange-correlation functionals
In the KS formulation of DFT[1][2], the total energy is given by
where the terms on the right-hand side represent the non-interacting kinetic energy of the electrons, the electrons-nuclei attraction energy, the classical Coulomb electron-electron repulsive energy, the exchange-correlation energy and the nuclei-nuclei repulsion energy, respectively. The orbitals and the electron density that are used to evaluate are obtained by solving self-consistently the KS equations
The only terms in and in the KS equations that are not known exactly are the exchange-correlation energy functional and potential . Therefore, the accuracy of the calculated properties depends mainly on the approximations used for and . Several hundreds of approximations for the exchange and correlation have been proposed[3]. They can be classified into several types, like the local density approximation (LDA), generalized gradient approximation (GGA), meta-GGA, and hybrid. Functionals that include van der Waals corrections have also been proposed. More details on the different types of approximations available in VASP and how to use them can be found in the pages and subcategories listed below.
How to
- Semilocal functionals:
- Hybrids: LHFCALC and list of hybrid functionals
- DFT+U: LDAU and LDAUTYPE
- Atom-pairwise methods for van der Waals interactions (selected with the IVDW tag):
- Methods from Grimme et al.:
- Methods from Tkatchenko, Scheffler et al.:
- dDsC dispersion correction
- DFT-ulg
- Nonlocal vdW-DF functionals for van der Waals interactions: LUSE_VDW
References
Subcategories
This category has the following 5 subcategories, out of 5 total.
Pages in category "Exchange-correlation functionals"
The following 96 pages are in this category, out of 96 total.