Questions tagged [pseudopotentials]

Refers to the approximation of core electrons by effective potentials. Used in plane-wave and Gaussian based theories.

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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 ...
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Are meta-GGA functionals SCAN (and its variants) ok to use in planewave DFT with the PBE pseudopotentials?

The meta-GGA SCAN functional has been there for a while. Despite the lack of SCAN (ultrasoft/PAW) pseudopotentials, various works used it in plane-wave pseudopotential calculations with ...
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Evaluate the orbital magnetic dipole moment within the PAW sphere

In general, the orbital magnetic dipole moment operator is defined as: $$- {e\over2} \mathbf{r \times v} \tag{1}$$ $\mathbf{v=p}/m$ is true only for simple Hamiltonian like $-1/2\ \nabla^2+V$, but not ...
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When are atomic-orbital-basis (rather than plane-wave) methods appropriate in periodic DFT

For example, GPAW supports both plane-wave and atomic-orbital basis methods. I know that atomic-orbital basis methods can have difficulty with electrons occupying vacancies for example, but what ...
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What is the difference between Ultrasoft, ONCV and PAW Pseudopotentials? Which is better for a spin-orbit coupled calculation?

I am trying to do spin-orbit coupled calculations for various topological insulators. I have found papers using Quantum Espresso with ONCV pseudopotentials and papers using VASP with PAW ...
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Are there properties that can only be calculated with a given set-up?

If you do a bibliography search about the codes used in matter modeling, you will find a large list. I played with a few of them (both free and commercial) and one of my findings is that the ...
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155 views

What are the types of pseudopotentials?

I would like to know what are the different types of pseudopotentials, the pro and cons, and what properties can/cannot be calculated with them?
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How do I generate an aluminum force-field for a LAMMPS input file? [closed]

I have been assigned a project on the generation of a force-field of Al (aluminum) for a LAMMPS potential. I have no idea how to proceed and what to do next. Can anyone please let me know how should I ...
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How to convert Unified Pseudopotential Format (UPF) into Ultrasoft Pseudopotential (USPP) format?

I am working on DFT code having plane wave along xy axis and bspline in z direction. For calculating the properties of TMD materials, spin orbit coupling must be included but i did not find fully ...
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How to generate relativistic pseudo-potential using Vanderbilt USPP that captures spin-orbit coupling?

I have used Vanderbilt USPP for generating a pseudopotential that does not include the spin-orbit term. But I want to have the spin-orbit coupling term included in the pseudopotential, to do ...
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Can GW-BSE quasiparticle calculations only be run on norm-conserving pseudopotentials (NCPPs)? If so, why not?

I've read in some texts that GW-BSE quasiparticle calculations have only been implemented on Norm-conserving Pseudopotentials (and not Ultra-soft or PAW PPs). Is there a conceptual reason for this? I ...
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VASP Dielectric constants: What potential to use?

I've simulated the dielectric constants using the LEPSILON = .TRUE. tag and the PBE GPAW potentials. A collegue mentioned that for accurate results norm conserving pseudo-potentials are the way to go. ...
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Understanding the GTH Pseudopotential

I'm new to DFT. I want to make use of the GTH pseudopotential. I am trying to understand how this potential works. I read the article "Separable dual-space Gaussian pseudopotentials" by S. Goedecker, ...
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Norm-Conserving or Ultrasoft, which pseudopotential to choose?

Ultrasoft pseudopotential (USPP), in general, requires a lower energy-cutoff to the plane waves when compared to Norm-Conserving ones (NC). On the other hand (at least with Quantum ESPRESSO) the ...
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How to generate a pseudopotential for a cation/anion?

Many DFT codes use pseudopotentials to represent the electron-ion interaction (as do most plane-wave codes and in contrast to so-called "all-electron" programs). There are several resources on the ...
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When do relativistic effects need to be explicitly included?

For many applications with heavy metals, pseudopotentials can be used to include some amount of relativistic effects. But for what sort of systems does it become necessary to actually use a ...
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When should I include semi-core electrons in DFT calculations?

Many DFT codes use pseudopotentials (for the core electrons) and basis set functions (for the valence electrons) in order to solve the Schrodinger equation. This is due because simulate each electron ...