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Questions tagged [quantum-espresso]

Questions related to the open source materials modeling framework, Quantum Espresso.

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3 votes
0 answers
28 views

Why do certain atoms remain fixed during relaxation?

I am running PBE defect calculations on InAs in Quantum Espresso. Whenever I run relax, the first 8 atoms stay fixed in place, while the rest displace by some amount. For example, ...
2 votes
0 answers
12 views

Is there any tool/website available by which I can generate VASP input files?

I am familiar with QE input files, but totally new in VASP. I know by using the quantum espresso input generator(https://www.materialscloud.org/work/tools/qeinputgenerator), we can use CIF file to get ...
4 votes
1 answer
36 views
+50

How to convert epsilon_2 to absorbance in optical calculation? DFT, RPA, Quantum ESPRESSO

I have a calculation via DFT-RPA, which calculates epsilon_2 and energy (eV). For optical property calculation, we usually plot epsilon_2 vs energy (eV). However, I need to know to convert the y-axis ...
5 votes
0 answers
18 views

Relax calculation of TMDC heterostructure

I am performing relax calculation on WS2/CrN heterostructure and it has already taken more than 10 days. I am not sure if some parameter is off in my input file. Is ...
4 votes
2 answers
137 views

How to make Quantum espresso input file from Vesta?

here is the CIF file of CaCO3 (http://www.crystallography.net/cod/1010962.html). I have opened it using Vesta and get the following data: ...
6 votes
1 answer
123 views

What's the temperature of the output electronic properties get from Quantum Espresso/VASP, even if we use 298 K cell info (atom position) as an input?

Normally to prepare input file (structure of materials) for Quantum Espresso/VASP, I searched the corresponding CIF file from this website (http://www.crystallography.net/cod/result.php), after that I ...
6 votes
1 answer
38 views
+50

Has anyone used Critic2 with Quantum ESPRESSO? Need help to determine non-nuclear charge determination

I have installed Critic2. Need to know how to determine interstitial site locations of a structure and their charges in those sites (in non nuclear maxima sites). I have calculated 3D charge densities ...
2 votes
0 answers
28 views

Methods of convergence in GW-BSE calculations: Quantum ESPRESSO and BerkleyGW

I have been learning BSE calculation through Quantum ESPRESSO and BerkeleyGW. I have been successful to obtain the silicon optical spectra (via GW-BSE), as instructed in the tutorial. The values of ...
3 votes
0 answers
25 views

Quantum ESPRESSO: how to calculate mobility?

How to calculate the mobility? Could you please share with a simple example (or simpler equation) to do this? Or in other words, if we have $E_g$, $E_F$, $P$, $V_{cell}$, $E_{vb,max}$, $E_{vb,min}$, $\...
2 votes
0 answers
19 views

Investigation of ferro, ferri, antiferro, para and dia magnetism using QE

Can Quantum ESPRESSO be used to investigate ferromagnetism, ferrimagnetism, antiferromagnetism, diamagnetism, and paramagnetism? If so, could you please elaborate on how these types of magnetism are ...
4 votes
1 answer
49 views

How to get 192 of CeO2 atoms coordinates using Vesta?

Here is the CIF file of CeO2 (http://www.crystallography.net/cod/1562989.html). One of the paper mentioned that they have used 192 CeO2 atoms constructed by 444 primitive cells. To generate the ...
3 votes
0 answers
17 views

Result of FTIR and RAMAN calculations for SiPOCa structure

Using Quantum Espresso models this structure with the following input files. However, the ph.x IR column always shows zero. Does anyone know why this result? ph.x input: ...
7 votes
1 answer
85 views

Does the size of atoms influence the speed of DFT calculations when comparing systems with almost the same number of atoms

How does the size of atoms within a structure influence the speed of DFT (Density Functional Theory) calculations? considering that the calculation speed is known to scale cubically with the number of ...
5 votes
1 answer
213 views

Calculating structural stability of a doped plane

The following image indicates an equation published on a reserach paper which was used to calculate structural stability in a metal atom-substituted graphene sheet. Can anyone tell me if we should ...
7 votes
0 answers
69 views

Correct method for structure optimization using DFT tools

Lets's say I want to start off DFT calculations for a material whose experimental cell constants are known. So I have two ways to get the correct structure to later on calculate, say, band structure ...
2 votes
0 answers
36 views

Stiffness constants C11

How can I accurately extract and reproduce the values of $C_{11}$ for 2D hexagonal structures with two independent in-plane constants $C_{11}$ and $C_{12}$? I've used Vaspkit to extract a value of ...
4 votes
0 answers
33 views

Time efficient way of conducting vc relax calculations while mainting accurate results at the same time

I believe this VC-relaxation calculation will take a significant amount of time to successfully complete. Referring to the literature (which indicates that the vanadium substitution atom is positioned ...
1 vote
0 answers
35 views

Formation and Optimization of Dimers, Trimers, Tetramers, and Beyond

What is the procedure to follow in order to computationally create clusters such as dimers, trimers, or tetramers using Quantum ESPRESSO?
2 votes
1 answer
43 views

Unit cell size for phonon modes

Based on this and some other literature I realize that the number of phonon modes is contingent upon the size of the unit cell. I also understand that in using Quantum ESPRESSO, the study of defects ...
5 votes
1 answer
40 views

Phonon calculations related problems

I am performing phonon calculations ph.x of CsPbBr3 primitive cell in QE v7.2 and it is taking a long time on ...
1 vote
0 answers
13 views

How can i do a variable cell relaxation under the influence of constant field in GPAW?

As a continuation of my previous question, I would like to do variable cell relaxation of a BaTiO3 unit cell under the influence of a constant electric field. The script I've used is given below: <...
4 votes
0 answers
23 views

How to calculate the volume energy loss function (VELF) using Quantum ESPRESSO?

How to calculate the volume energy loss function (VELF)? Could you please share with a simple example (with related input files, output files and/or plot)? Any relevant links would also be welcome.
12 votes
1 answer
130 views

Which data files need to be stored after publishing a DFT study?

When we browse literature on first-principle study, we see they usually report the methodology, used program with the version number and the results. In some cases, people share their input files, ...
6 votes
1 answer
87 views

Should alat value be used as it is in calculation or multiplied with CELL_PARAMETERS value?

I am trying to perform DFT calculations for CsPbBr3 system on QE v7.2. To exploit symmetry i have given the space_group=221 and ...
4 votes
1 answer
122 views

Is it possible to do a vc-relax calculation using GPAW?

I wanted to do a variable-cell relaxation calculation using GPAW (similar to the one present in quantum ESPRESSO). It would be nice if I could get pointers on how to approach this. ...
3 votes
0 answers
17 views

The relationship between Partial charge & Lowdin charge in Quantum espresso.?

I got Lowdin charge distribution from Quantum espresso calculation. But I have a difficulty in converting from Lowdin charge to partial charge. The formula is " (partial charge) = (Lowdin charge) ...
5 votes
1 answer
80 views

projected DOS with hybrid functionals using Quantum Espresso

I wish to compute the projected density of states for a system by employing hybrid functionals. I am aware that the band structure can be computed using either the Wannier90 approach or using ...
3 votes
0 answers
29 views

Error in ph.x file

I ran this ph.x file for my structure. However, this response error was displayed. Observation: I made my scf file with norm conserving pseudopotential. The result was ok. Input: ...
4 votes
0 answers
58 views

Diagnosing faulty bands calculation

Using QE v6.7, I computed the bands structure of CsPbI3 and I am not happy with the results. The Problem While performing the nscf calculation I kept getting the ...
5 votes
2 answers
84 views

Why my Relax calculation is not stopping?

I am conducting a relaxation calculation on a mono-layer of MoS2 with a 3x3x1 super-cell, where one Molybdenum (Mo) atom is substituted with a Palladium (Pd) atom defect. However, the calculation is ...
4 votes
1 answer
53 views

Can we use formation/ cohesive energy to express the structural stability of a supercell?

I have created a graphene supercell using Quantum Espresso and performed a vc-relaxation on it. Now, I need to verify whether the created structure is stable and demonstrate its stability with ...
2 votes
1 answer
44 views

Structural stability of Graphene

is it acceptable if I came up with around -8.5ev/atom for cohesive energy of graphene?, Literature is in the range 7.3-7.9 ev/atom The formula used for cohesive energy calculation Codes I have used ...
7 votes
1 answer
113 views

Stopping an ongoing relax calculation with provision to continuing the calculation later on from that checkpoint

How can I interrupt an ongoing relaxation calculation in Quantum ESPRESSO on my system, while ensuring that I can resume it later from the same point?
2 votes
0 answers
24 views

Making a mirror structure of a structure from Quantum ESPRESSO input file

I have two Quantum ESPRESSO input files. They are supposed to be mirror like. I want to check whether they are actually mirror or not. Is there any tool or way to convert one structure to it's mirror ...
3 votes
1 answer
61 views

what determines the 'Estimated total dynamical RAM ' in a Quantum Espresso calculation

As per my understandings the computer resources required for a DFT calculation increases by an order of three with the number of atoms. But as you can see in the output files given below the ...
4 votes
1 answer
72 views

Introducing a vacuum space in z direction for 2D monolayer calculations

Is the introduction of a vacuum in the z-axis necessary when utilizing a 2D monolayer material for Density Functional Theory (DFT) calculations in Quantum Espresso? (This is due to the fact that only ...
3 votes
0 answers
38 views

How to undo the periodic boundary conditions for supercell calculations

I am using Quantum Espresso to study defects in III-V materials, and recently I relaxed my defect system in a 64-atom supercell. Currently, I am trying to determine the ionic displacements relative to ...
2 votes
1 answer
41 views

vc-relax calculation on two-dimensional slab

Is performing only a relaxation calculation (calculation='relax') sufficient for geometrical optimization in conducting a density functional theory (DFT) study of ...
5 votes
1 answer
83 views

How to determine energy convergence threshold and force convergence threshold in Quantum Espresso [closed]

In the computational investigation of $MoS_2$ monolayer for its catalytic activity in the hydrogen evolution reaction, how are parameters such as forc_conv_thr and <...
9 votes
1 answer
281 views

Comparing results of various DFT calculations in Quantum ESPRESSO

To verify the reliability of calculation scheme, I want to compare lattice constants, bond length and band gap calculated by the different functionals with the experimental results. So in order to do ...
1 vote
0 answers
23 views

Applying Pressure in z-direction in quantum espresso

I am working with Bilayer 2H-MoS2, interlayer spacing ~3A. I want to apply pressure in z-direction which can lead to reduction in interlayer spacing, and then calculating its electronic properties. so,...
5 votes
1 answer
87 views

Non-monotonic behaviour in calculation time with changing 'degauss' value of 'cold' smearing

"I conducted a convergence test for the degauss value in Quantum Espresso input with smearing = 'cold'. The results, ...
6 votes
1 answer
56 views

VASP & Q.E - Crossing in the band structure in Weyl (nodes) and Dirac materials

I was doing some calculations involving Selenium (my advisor gave me this "task" as training. I'm an undergraduate student.), which exposes the Weyl nodes in its band structure, and I tried ...
1 vote
0 answers
74 views

Can I use the convergence test results of ecutwfc, ecutrho, and k points obtained from a 2x2 graphene supercell for a larger graphene supercell?

Recently, I conducted convergence tests (ecutwfc, ecutrho, and k points) for a 2x2 graphene supercell, yielding results of 120 Ry, 300 Ry, and 10x10x1 respectively. (Here, we considered convergence ...
5 votes
1 answer
47 views

Error in calculating FTIR and RAMAM using Quantum Espresso

I ran the following FTIR and RAMAN codes using Quantum Espresso. However, the calculations have not finished, can anyone tell me if my input files have any errors? ph.in ...
3 votes
1 answer
88 views

At a particular K-point (Monkhorst Pack) grid, SCF calculation is not converging

During a convergence test of (MoS2 2x2x1) monolayer using Quantum ESPRESSO, I tried several K-point Monkhorst-Pack grids. According to my understanding, the calculation time and computational cost ...
6 votes
1 answer
536 views

Understanding algorithm of Quantum ESPRESSO from scratch

As someone new to this field, what are some effective strategies or resources I can utilize to study and understand the Quantum ESPRESSO algorithm from scratch?
7 votes
1 answer
198 views

Convergence testing in DFT calculation

I have done convergence testing for MoS2 (2x2x1) monolayer structure in the following order: ecutwfc ecutrho k_points After setting these values, I would like to include vdW correction to the system ...
4 votes
0 answers
31 views

Exicuting Quantum espresso vc-relax/relax calculation crashes with an error message saying more bands than PWs

I wanted to perform a vc-relax calculation for the FeS2 lattice with 12 atoms. The error message reads as follows for every tasks from 1 to 12. ...
3 votes
0 answers
37 views

Energy corrections to be added in my DFT input of Quantum ESPRESSO for studying catalytic activity of MoS2 for hydrogen evolution reaction

While investigating 'catalytic activity of MoS2 (monolayer) in hydrogen evolution reaction', what are the energy corrections that I am supposed to add in the DFT input (using Quantum ESPRESSO) to get ...

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