New answers tagged density-functional-theory
8
votes
Why is Young's modulus represented as a single value in DFT calculations?
If you perform an elasticity calculation in DFT, you typically calculate stresses in a series of strained cells, and fit the elastic constants against these stress-strain relations. The lower the ...
- 1,526
2
votes
How can I use vasp for calculating different cell volumes by adjusting cell parameters
Generalized optimization in computational materials science involves adjusting both atomic positions and simulation cell parameters to minimize the system's energy/forces/stress. The goal is to reduce ...
- 4,396
3
votes
How can I fix wrong number of k-points error in Qantum ESPRESSO while running pw2wannier90.x?
The problem is in either your seedname.win or your pw2wan.in file, actually. The hint is in the error message: pw2wannier90 ...
- 1,116
2
votes
3
votes
Why converge energy vs. Ecut when k-points is the bottleneck?
You should really consider your choice of convergence criteria bearing in mind the eventual target calculation. If your goal is to calculate a chemical reaction energy, then yes, the energy residual ...
- 681
3
votes
Why converge energy vs. Ecut when k-points is the bottleneck?
Convergence is all about finding a suitable balance between cost and accuracy, and putting some sense of errors on your results.
Typically, you should have a think about the accuracy you require for ...
- 495
5
votes
Why does increasing the cell size affect the energy of molecules?
The issue was that I used too large of a grid spacing at 0.26 Å. This value I got from a utility tool from GPAW, cutoff2gridspacing. From an old convergence test with VASP on similar systems the ...
- 183
0
votes
Effect of number of component and How to plot DOS
In my first question, the answer i found is band folding.
Why is the band structure of a supercell more dense than for simple cell?
in stead of explaining, i leave the link.
But 2nd question is under ...
- 91
1
vote
van der Waals interactions?
No. In quantum espresso, you don't need to add any additional files to add the DTF-D3 van der Waal's corrections. You just have to specify vdw_corr = 'grimme-d3' ...
- 1,154
1
vote
How to Optimize Atomic Positions and Volume While Preserving Cell Shape in VASP?
In my case, I use ISIF=3 at first, then ISIF=2.
Because my starting poscar comes from an already optimized cif file.
But if you are generating a poscar file, I recommend using ISIF=7 at first.
Then ...
- 91
0
votes
Accepted
how to model gate oxide in transiesta?
The accepted answer is not, strictly, correct. Siesta (and thereby TranSiesta) enables charge distributions acting as gates.
So, while you could add the full SiO2 layers in a transiesta calculation, ...
- 4,394
7
votes
What is the proper interpretation of the output 'HF' energy of a ground-state Gaussian 16 calculation using the opt keyword (B3LYP)?
From the Gaussian 16 FAQ:
The full breakdown of the energy is not part of the normal output, but you can get it with two changes change to your input. First, add ExtraLinks=L608 to the route section ...
- 24.2k
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