Questions tagged [exchange-correlation]

Questions concerning exchange-correlation terms in materials modeling calculations.

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12
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1answer
98 views

What's the physics contained in the exchange-correlation functional in the framework of KS-DFT?

This question is inspired by this post. In the Kohn-Sham framework of density functional theory, the total energy is expressed as: $$E=E_{kin}^{non}+E_{ext}+E_{H}+E_{xc}$$ in which The first term is ...
9
votes
1answer
225 views

How does libxc calculate the potential of GGA functionals?

If the GGA xc energy is defined as $$ E_{xc}[n] = \int n(\mathbf{r}) \varepsilon_{xc}[n(\mathbf{r}), \nabla n(\mathbf{r})]\ d\mathbf{r}, $$ the potential can be written as $$ V_{xc}[n] = \varepsilon_{...
8
votes
1answer
63 views

Parameterization in the generalised gradient approximation (GGA)

Disclaimer: Assume the person asking is a novice in DFT and condensed matter physics in general. In the localized density approximation (LDA), the exchange correlation potential is considered a ...
3
votes
1answer
85 views

The projector augmented wave (PAW) method, pseudopotentials (PP), and exchange correlation functionals

Disclaimer: Assume the questioner is a novice in DFT Is PAW an improvement over the pseudopotential method? In terms of Perdew, Burke, and Ernzerhof (PBE) parameterization, what is the difference ...
28
votes
2answers
635 views

Is there any DFT code or software that has the option to use this exact exchange-correlation energy functional?

Most of the conventional DFT codes or software use LDA, GGA, meta-GGA, PBE, etc. exchange-correlation functionals, but I'm wondering if there is any DFT code or software that uses the new generation ...