Questions tagged [vasp]
Questions about or related to the Vienna ab-initio Simulation Package (VASP).
462
questions
2
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0
answers
100
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study of elastic properties under pressure using VASP [closed]
I want to replicate this paper, but somehow I cannot get the same results, most important as shown in table 2. Can anyone help me with this?
I have attached the INCAR file. If any correction is needed,...
- 529
5
votes
0
answers
373
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VASP DFT+U on Ti d orbital, why d orbitals are not affected but s and p orbitals are pushed lower? [closed]
I'm using DFT+U implemented in VASP to calculate the electronic density of states of anatase TiO2.
In order to more accurately reproduce the experimental bandgap of anatase TiO2 (as compared to ...
- 157
2
votes
0
answers
2k
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Setting MAGMOM in VASP for possible Magnetic configurations [closed]
I have been working with a material in which Cu has an unpaired electron due to which the material can exist in various magnetic configurations. I wish to see how various properties change as I switch ...
- 1,641
4
votes
2
answers
268
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VASP structure relaxes to an incorrect ground state
I am using VASP to perform a structural relaxation of $\ce{CuNCN}$. I am using the PAW-PBE POTCAR files for the same and the KPOINTS have been generated using a script. The POSCAR file has been ...
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3
votes
1
answer
408
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DFT-D2 calculations in VASP and Gaussian
We are planning on comparing the results of Quantum dots and Bulk materials for our systems so we are planning to use Gaussian for QD and VASP for Bulk. Considering that we will be comparing their ...
- 1,641
6
votes
1
answer
463
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How to transform the k coordinate into the k path used in the band structure?
When drawing the band structure, I need to transform the coordinate of k-points into a k-path, but I am not sure what the formula is.
I checked the result of siesta,...
- 1,977
3
votes
0
answers
135
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Anti ferromagnetism of the Entropy Stabilized Oxide (ESO) [closed]
I want to do a simple SCF calculation for an entropy stabilised oxide using VASP (DFT code). The chemical formula is (CuCoMgNiZn)O (Rock salt structure) and it is anti-ferromagnetic in nature. I am ...
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1
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0
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200
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how to choose a basis set when calculating COHP? [closed]
I am trying to use the lobster program to calculate COHP, according to the explanation in the literature, it is better to add unoccupied atom orbitals into the basis set.
The initial step in ...
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6
votes
1
answer
500
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Is it possible to build a force field that suits all elements based on VASP's machine learning result?
I have tried to use VASP's machine learning force field calculation during running molecular dynamics simulation with a supercell including some elements of Ti, O, Cu, etc. It does increase the speed ...
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3
votes
1
answer
331
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Coulomb energy in VASP
In DFT, the Coulomb energy is defined as the sum of Hartree energy, nuclear-electron attraction, and nuclear-nuclear repulsion. In VASP output, we can find the Hartree energy, and also the nuclear-...
2
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0
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351
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Why does the GPU version of VASP consume a lot of time on STRESS calculation? [closed]
I am trying to compare the CPU and GPU versions of VASP.6.3.0, it seems that the GPU version consumes a lot of time on the STRESS item, does it represent the time for calculation stress tensor?
Here ...
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2
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0
answers
48
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How do I find out the subdivisions N_1, N_2 and N_3 in BAND STRUCTURE? [closed]
I want to find out how to get subdivisions from vasprun.xml of Brillouin zone. Does anyone know how to do this?
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7
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1
answer
177
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What is the best cell shape to calculate the energy of a free atom with a periodic DFT code (VASP)?
I want to study the adsorption energies of many different atoms to some surfaces. For that, I need to calculate the energies of free atoms (adsorbates) in a vacuum.
I understand that I am supposed to ...
4
votes
1
answer
687
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Why I have difference between DOS and BAND gap?
As they advise everywhere, SKF should be considered without SOC, and already in NSCF, spin-orbit interaction should be included. But what is the actual question, as I know, band splitting occurs with ...
- 61
8
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4
answers
2k
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DFT code for simulating thousands of atoms in a supercell
I'm trying to simulate a supercell that contains thousands of atoms with the DFT method, but it seems VASP couldn't handle such a large system, its parallel efficiency is relatively low, when I try to ...
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1
vote
0
answers
67
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how to simulate the size effect with DFT theory?
I am considering simulating the size effect of nanoparticles, the size expands from 0.2nm to 50nm, but when trying to build the model, I am not sure how to reflect the size correctly, for example, if ...
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4
votes
1
answer
213
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How to save the generated 3d representation of the structure(s) by Viewer3d in Py4vasp?
I used py4vasp to calculate structure from data and then I displayed them in a structure viewer (Viewer3d) by this line: calc.structure[:].plot(). It returns a ...
6
votes
1
answer
528
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How to do simulation when two atoms exist in the same coordinate position in the lattice?
I found that there is a type of substance in which two atoms exist in the same coordinate position in the lattice, for example, FeF3(H2O)3, here is its crystal ...
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6
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1
answer
363
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Effective mass of holes was measured using DFT
Effective mass of holes was measured using DFT. The hole value is different for each band, is there a way to get the average or standard value of this value?
It was calculated using the VASP program.
...
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7
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1
answer
351
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Why can't DFT calculate the accurate electronic configuration of the Oxygen atom?
I am trying to do a DFT calculation of Oxygen atoms with the VASP code. My settings follow the official tutorial on the Oxygen atom of VASP. But it turns out the energy levels of the two spin ...
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6
votes
0
answers
647
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How to calculate the Gibbs free energy for a reaction? [closed]
I am trying to learn how to calculate Gibbs free energy for a reaction. Assuming a reaction for two-dimensional TMDCs:
MoS2 (solid) + 2Se(gas) ---> MoSe2 (solid)+ 2S (gas)
I can calculate the ...
- 1,426
10
votes
2
answers
755
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How to calculate temperature dependent phonon band structure in VASP
I want to calculate phonon band structure using VASP for a double perovskite $\ce{A2BB'X6}$.
Most of the perovskites are well known for dynamical instability at $\pu{0K}$ but show a dynamically stable ...
- 1,663
3
votes
1
answer
760
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NCORE bigger than 1 when performing phonon/vibrational calculation(IBRION=5) in VASP?
When I try to calculate the vibration frequency of TiO2, I set IBRION=5 in VASP, but it turns out I couldn't use NCORE>1 in this situation, once I use NCORE>1, VASP would run for only one ionic ...
- 1,977
4
votes
0
answers
124
views
The ionic step is not convergent when doing DFPT in VASP [closed]
I am trying to do DFPT, during the process of moving in different directions, even I set EIDFF=1E-8, the corresponding ionic step is not converged, the relative ...
- 1,977
4
votes
1
answer
187
views
Decide the position of oxygen vacancy via the configuration with the lowest energy?
I am trying to determine the position of oxygen vacancy in $\ce{TiO2}$, is it reasonable to decide it by choosing the configuration with the lowest energy?
It doesn't feel quite right to always choose ...
- 1,977
5
votes
3
answers
302
views
Gibbs free energy modification after finishing NEB?
I have finished the NEB calculation, but it seems all the energy I got is Internal energy instead of Gibbs free energy, so do I need to do Gibbs free energy modification? Is there any standard ...
- 1,977
4
votes
1
answer
2k
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Reciprocal lattice and k-lattice belong to different groups in VASP
I am trying to do geometry optimization of TiO2 with VASP.
Here is the POSCAR file, which I get from the Materials Project.
...
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4
votes
1
answer
1k
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Why does the temperature fluctuate severely during the AIMD using an NVT ensemble?
I am trying to raise the temperature of my model and keep the temperature at 300K, with an NVT ensemble and Nose-Hoover thermostat.
I am doing this job with VASP, here is the ...
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3
votes
0
answers
339
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Problem while performing the BSE GW calculations in VASP
I am trying to learn the BSE GW calculations in VASP. Using the procedure described on the VASP website.
I am stuck at the last step 5 (BSE calculation). I didn't get any error in the 5th step but ...
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4
votes
1
answer
426
views
Elastic constant calculation
I want to calculate elastic constants with VASP "by hand" (not by, e.g., DFPT) as I have a big structure (64 atoms). For this, I am making tests on $\ce{Si}$ at the moment.
So, I have done ...
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5
votes
0
answers
79
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"Failed" running DDEC6 Atomic Charge when using Palladium (Pd) cluster model [closed]
I have a problem with running DDEC6 when I used Palladium (Pd) cluster, the main issue was that there were no DDEC6_even_templered_net_atomic_charges.xyz files came ...
- 51
5
votes
0
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275
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Optical Property calculation in VASP using HSE [closed]
I have calculated frequency-dependent dielectric constant in VASP using PBE exchange-correlation functional, within the framework of Independent particle approximation (with RPA). I want to perform ...
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6
votes
1
answer
963
views
How to calculate the magnetic anisotropy energy using the VASP code?
I want to calculate the magnetic anisotropy energy of the CrI$_3$ monolayer which has 8 atoms per unit cell. I have understood from VASPWIKI that there are two steps:
A standard SCF collinear ...
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3
votes
0
answers
248
views
RPA calculations with Hybrid Functionals [closed]
When doing RPA calculations as explained here, if I want to calculate it with hybrid PBE0 should I put LHFCALC = .TRUE. for just step 1 or step 1, step 3 and step 4?...
4
votes
1
answer
165
views
What are the precise forms for the SU(2) and rotation matrices in VASP?
Some time ago, I conducted a discussion with Dr. Gui-Bin Liu on topological materials here. One relevant thing he said was:
"The format of trace.txt file is only a necessary condition to be used ...
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4
votes
1
answer
337
views
Evaluating absorption coefficient using VASPKIT for nanostructures (specifically quantum dots)
I was planning to use VASPKIT in order to determine the linear optical properties of my nanostructure. But upon running VASPKIT, I do not see an option for 0D materials but only for 2D and bulk.
Is ...
- 1,641
7
votes
1
answer
475
views
Minimum number of kpoints for calculation of properties of nanoparticles in vasp
I am a little confused about what should be the correct number of kpoints that I wanna use. I am currently working on a small cluster so picking a high value(even around 10) gives me a memory fault. ...
- 1,641
7
votes
1
answer
537
views
The relationship between average eigenvalue and convergence performance in VASP?
I meet some convergence problems when doing self-consistent field calculation in VASP, I find some parameters on VASP wiki that might be able to tune the convergence performance. But I don't quite ...
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6
votes
1
answer
602
views
Reorder the atoms in the POSCAR file
I want to rearrange the order of the atoms in the POSCAR file, is there any software able to do this? For example, in the below POSCAR file, I want to put Ti atoms before others.
...
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7
votes
1
answer
198
views
Which atoms should be fixed when simulating metal oxides surface relaxation?
I am trying to model the surface relaxation on the TiO2(Anatase-101) surface, but it confuses me that when I try to set some atoms as fixed, unlike the crystal that only contains one element, there is ...
- 1,977
6
votes
4
answers
3k
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Unable to install P4Vasp
I am currently learning how to use VASP and was looking at how to get the DOS plots. I have been recommended to use P4VASP but due to some reason I am not able to install it on my Ubuntu 20.04. When I ...
- 1,641
1
vote
0
answers
213
views
can anyone please explain what is meaning of band.conf , mesh.conf and pdos.conf in phonon calculation? [closed]
Can anyone please explain, what is the physical meaning of band.conf, mesh.conf and pdos.conf in phonon calculation?
if it is possible please explain about tags used in it.
- 529
6
votes
0
answers
137
views
DFT+U for RPA Ground State
For RPA calculations in VASP, a four step process can be utilized where the first step is to compute the occupied orbitals at either the GGA or hybrid GGA level.
I am curious with materials that are ...
- 10.8k
9
votes
2
answers
1k
views
How is the right k-path chosen for band structure?
When generating the kpoint by vaspkit for two compounds that have the same lattice system, I found the kpath is
G–X–S–Y–G–Z–U–R–T–Z|Y–T|U–X|S–R.
But why in the article (as shown in the picture) was a ...
- 547
9
votes
2
answers
432
views
Why do we need to use fake k-points when doing HSE band structure in VASP?
I want to know why we need fake k-points in HSE band structure calculation? I mean why we can't take a simple high symmetric path like we do in PBE calculation?
5
votes
0
answers
130
views
VASP calculation of entropy stabilised oxide (ESO) [closed]
I want to do a simple SCF calculation for an entropy stabilised oxide (a kind of high entropy alloy) using VASP (DFT code). The chemical formula is (CuCoMgNiZn)O (Rocksalt structure). I am considering ...
- 866
8
votes
2
answers
255
views
How to calculate circular dichroism in VASP?
Is there an option to calculate circular dichroism (CD spectra) and anisotropic Dissymmetry factor in VASP.
I need to calculate the spectra for chiral system
- 547
5
votes
1
answer
704
views
Convert a POSCAR-format-like file to a XSF file?
How do I convert a POSCAR-format-like file to a XSF file (visualized by XCrySDen)?
I'm looking for a step by step tutorial on the process and what tools/programs are needed.
- 547
3
votes
1
answer
384
views
How to start with the elastic properties of 2D materials using the VASP code?
I have some experience in dealing with structural, electronic, and magnetic properties of 2D materials, but I want to go further to study the elastic properties. Could you please guide me on this? ...
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6
votes
1
answer
165
views
What does GGA_COMPAT do in VASP and why is it recommended to set it to FALSE for non-colinear calculations?
Why is it recommended to set GGA_COMPAT = .FALSE. for non-colinear calculations? Could someone explain what GGA_COMPAT does?
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