New answers tagged density-functional-theory
3
votes
Why are my HPC calculations not running in SLURM?
"I still didn't see an output from my calculations from the HPC."
This is because your jobs had not yet started. I can see this based on the squeue ...
- 33.6k
3
votes
Bader charge calculation in Quantum ESPRESSO DFT
As far as you have correctly obtained the charge density files, the procedure is straight forward.
I will assume that you have the all-electron density and the valence electron density. If not, then ...
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2
votes
How to set the LMAXMIX tag in VASP for the material BaLaMn2O6?
DFT+U is an advanced computational method developed specifically to enhance the accuracy of describing systems containing strongly correlated d or f electrons. These systems, such as antiferromagnetic ...
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3
votes
Spin-orbit coupling and lattice constant
It's hard to tell without any information about the material, but it could be a feature. It is known that transition metal compounds can have an involved interplay between spin-orbit coupling and the ...
- 4,696
2
votes
Is it possible to find H-bond enrgy with O-H distance less than 0.95A?
A short O-H bond (0.86 Å) is often wrongly observed in X-ray crystallography, but should give you no problems other than SCF problems. Having no experience with gaussian, my guess is that you are ...
- 1,034
4
votes
Accepted
Can the the relaxed energy of a material system (eV/atom) computed by DFT using VASP be positive?
When DFT is being used for electronic structure energy calculations, a negative energy would be indicative of bound electrons. There's nothing physically, chemically or mathematically illegal about ...
- 33.6k
4
votes
Can the the relaxed energy of a material system (eV/atom) computed by DFT using VASP be positive?
Firstly, by expressing the energy per atom (eV/atom), it allows for a more convenient comparison between different materials or systems, as it provides a measure of the energy on a per-atom basis. ...
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4
votes
Accepted
Determining the Nature of a Material's Band Structure: Metallic or Semi-Metallic?
(Edited after discussion with the asker and seeing the zoomed-in band structures. A commenter suggested adding Addison of hybrid functionals as a correction to the band gap underestimation of [...
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3
votes
Adsorption of Li on GeC (optimization problem)
The adsorption energy of Li or K atoms on a GeC sheet is influenced by several factors, including the electronic structure, bonding interactions, and surface reactivity of the materials involved. If ...
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3
votes
How to calculate the charge density using Quantum Espresso?
In recent versions of Quantum ESPRESSO (I'm looking at 7.2), you likely already have a charge density file written. Inside your ...
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0
votes
How to read UPF pseudopotential for ultrasoft pseudopotential simple in a fortran program
For now, the UPF standard is defined on Quantum ESPRESSO's website. Looks like the documentation is for an XML-like format, but it will be (or has already been, ...
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11
votes
Accepted
Fermi Energy in Band Structure
In electronic structure calculations of finite systems, there is a well-defined energy scale: 0 is the vacuum energy, and any electron with positive energy is unbound.
For materials, the story is ...
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2
votes
Calculation of charge defect formation energy
First, the energy correction term, $E_{corr}$.
It arises due to presence of periodic boundary conditions (defects are spuriously repeated) and of background charge compensation (hidden from the user). ...
- 61
4
votes
Accepted
Optimal choice between ISIF = 3 and ISIF = 4 for lattice parameter and atomic position relaxation in VASP calculations
You've already summarized the differences in your question, but to be complete: ISIF=3 has an additional degree of freedom that allows the cell volume to change. In principle, there should be no ...
- 166
2
votes
Does VASP include energy penalty contribution in OUTCAR energy of constrained moment calculation?
A colleague shared with me that the energy VASP outputs does seem to include E_p, since different LAMBDA gave her different ...
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5
votes
What are the recent developments of TDDFT to simulate the excited properties of materials?
Time-dependent density functional theory (TDDFT) has indeed seen significant developments since its review in the classical paper you mentioned. One of the recent advancements in TDDFT is:
Nonlinear ...
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4
votes
What do we get by integrating over the charge density data of a material system calculated with DFT?
The integration of the charge density over the entire system gives you the total charge of the system. This value should be equal to the total number of electrons in the system, accounting for both ...
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1
vote
How may I calculate atomic orbital energies using VASP?
I will suppose that you have done the following as your approach looks correct, you shoud have performed an (SCF) calculation and include a sufficient number of bands to accurately capture the d ...
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