Questions tagged [quantum-espresso]
Questions related to the open source materials modeling framework, Quantum Espresso.
82
questions
7
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0answers
23 views
How do I get exact percentage of spin-polarization in Quantum ESPRESSO?
I am investigating a near half-metallic / high-spin polarization material. I ran an SCF calculation with nspin = 2, with some starting magnetization. So now I ...
7
votes
0answers
60 views
How to fix gauge in Quantum Espresso?
I am trying to use Quantum Espresso to manually calculate the Berry phase using the Berry connection, due to evolution along a closed loop in k-space. I want to do this manually instead of using ...
10
votes
1answer
64 views
Can I do a “constrained” geometry optimization in Quantum ESPRESSO, such that certain dopants appear in certain positions even after relaxation?
I am studying the magnetic properties of bulk ZnO, so I am doping it with transition metal elements in order to observe the magnetic spectrum. I replace a Zn atom with a transition metal element at ...
4
votes
1answer
46 views
How can I obtain seperate spin-up and spin-down bands while considering Spin Orbit Coupling in Quantum ESPRESSO?
I have been studying a magnetic material with SoC taken into consideration. The main aim was to obtain the band structure.
when I use spin_component = 1 in the ...
7
votes
1answer
66 views
How to understand the wavefunction outputed by QE with HDF5 format?
Following the answer to my question: What is the best program to manipulate numerical DFT wavefunctions to calculate custom matrix elements?,
I compiled Quantum ESPRESSO with the hdf5 flag on, and now ...
9
votes
2answers
85 views
Can we consider SOC in FM materials using QE?
This is a follow-up question to my question posted here. I've been trying to study the effects of spin-orbit coupling (SOC) on the band structure of ferromagnetic (FM) material VSe$_{2}$. The input ...
11
votes
1answer
44 views
How can I properly attach ligands to a surface?
The main aim of my venture is to study the effect of the presence of surface ions on the band structure of Si slab using Quantum ESPRESSO.
I've tried to use iQmol to attach ligands to the surface. The ...
10
votes
1answer
224 views
How to make sure that my SCF calculation is correct?
hope you are doing well.
I am trying to study the electronic properties of ZnO doped with transition metals (Co, Ni, Fe) using DFT calculation, I am a beginner on DFT calculation using quantum ...
5
votes
0answers
38 views
How to use hp.x in Quantum ESPRESSO to calculate Hubbard parameter
I want to work with GGA +U on Quantum espresso to calculate the electronic properties of Ni Co co-doped ZnO system, but I can't figure out how to use the hp.x program for my system to calculate the ...
8
votes
0answers
57 views
Band structure has unusual lines in the valence band using Quantum ESPRESSO
Currently, I am working on ZnO doped with nickel and cobalt.
I performed the SCF, NCF, BANDS calculation and got the results, the calculation converges without any errors.
After that I used BANDS.X to ...
12
votes
1answer
88 views
What is the best program to manipulate numerical DFT wavefunctions to calculate custom matrix elements?
For pedagogical reasons, I am looking for ways to calculate quantum-mechanical quantities such as $\langle m | \dot{m}\rangle, \langle m | \dot{n}\rangle, \langle m | \ddot{n}\rangle$ using ...
9
votes
1answer
100 views
Should I use a lower threshold for calculations involving SOC?
I'm studying a compound $\ce{VSe_2}$ using the DFT package Quantum ESPRESSO (QE). The following is the input file.
...
4
votes
0answers
26 views
Is there a way I could calculate the pressure and use SOC at the same time?
I have been trying to find the appropriate k-point grid via convergence in quantum ESPRESSO (QE). The following is my input file.
...
6
votes
1answer
38 views
Understanding QuantumEspresso Toolbox through Maestro
Anyone here uses Quantum Espresso through Maestro can tell me a bit more about the calculation panel setting:
I understand that -npools option must be divisible by ...
5
votes
1answer
58 views
How can I properly represent paramagnetic materials in DFT calculations?
I have seen specific ways of constructing input files for
Anti-ferromagnetic materials
Ferromagnetic materials.
How can I represent a paramagnetic material in plane wave DFT codes like Quantum ...
5
votes
0answers
35 views
At what threshold would I assure convergence?
I'm a beginner in DFT and Im using quantum espreso.
I've seen the difference of hydrostatic pressure being used as a criteria for converging my k-point grid and plane-wave cut-off values.
I would like ...
5
votes
0answers
23 views
Recommended code to do XAS/XES/RIXS calculations with?
I am a grad student looking to simulate several XAS/XES and potentially RIXS spectra for some strongly correlated metal-oxides. The materials in question will likely require solving the Bethe-Salpeter ...
7
votes
3answers
328 views
For which elements should I include spin orbit coupling in Quantum ESPRESSO?
I'm trying to study a Yb-Ge-Sb compound and would like to include spin-orbit coupling (SOC). In Quantum ESPRESSO, this is done by including the following tags in the ...
9
votes
1answer
346 views
How can I know if 3D aperiodic systems are not interacting with each other using Quantum ESPRESSO?
I wanted to observe the Projected Density of States of InP system passivated with Hydride ions. For that, the following input file was created.
...
5
votes
0answers
42 views
Is it necessary to terminate the surface ions in a quantum dot?
I was trying to study quantum dots of ZnO. But I'm pretty new to creating and passivating 0 D particles. Is it always necessary to passivate the free surface of the quantum dot? Regarding the studies ...
10
votes
2answers
231 views
How to perform charge analysis for a molecule
I am doing dehydrogenation of a molecule (say $\ce{C12H12}$) and I want to do charge analysis for dehydrogenated system ($\ce{C6H6}$). How I can proceed? I can use Quantum ESPRESSO and Gaussian ...
8
votes
2answers
126 views
inconsistent behavior between band structure and density of states
I'm a beginner in DFT calculation. I have performed a DFT calculation on CuCoSnSe using PBE-GGA on Quantum Esspresso. When I plot the band structure and the total DOS, the band structure shows a ...
4
votes
0answers
35 views
Incosistent charges and magnetic moments between SCF and PDOS calculations in Quantum Espresso
I have a system of 5 layers of an element + 1 layer of another one, I want the relaxed position of the last layer, and once I have it, proceed to calculate the pdos. I am performing simulations in the ...
7
votes
1answer
89 views
Smearing and charge balance for tungsten with interstitial oxygen in Quantum ESPRESSO
What smearing would be ideal for a bcc W with interstitial O atom. I am running 3x3x3 unit cells with one N interstitial.
I am having convergence issues in relax ...
12
votes
2answers
220 views
Getting different total magnetic moment in 'scf' and 'vc-relax' calculations in Quantum ESPRESSO
I am performing a spin polarized DFT calculations in Quantum Espresso on a Co2MnSi ferromagnetic crystal. For this I have performed these steps:
1) Performed ...
14
votes
3answers
685 views
Is it possible to calculate the Curie temperature for magnetic systems?
Using DFT calculations we can know the electronic and magnetic property of the system at 0 K. I am wondering if there is any computational method to know the curie temperature of magnetic materials? ...
9
votes
1answer
101 views
Is the “Final Magnetic moment” in the materials project repository same as the “total magnetization” value in Quantum ESPRESSO output files?
I'm quite new to spin-polarized DFT and have been trying to study $BaVSe_{3}$ which is ferromagnetic (with a Final Magnetic Moment of 0.052 Bohr Mag) as per the Materials Project repository [picture 1]...
8
votes
1answer
77 views
How to analyze the band symmetry with Quantum ESPRESSO?
This question is related to this paper: J. Phys. Chem. Lett. 2017, 8, 13, 2999–3007
The above figure shows symmetry analysis for the band structure. The author writes:
The band symmetry and parity ...
7
votes
1answer
42 views
Relax vs VC-Relax for interstitial incorporation energy
In order to model an interstitial trapped in a metal lattice, and the associated incorporation energy, which should be used - "relax" or "vc-relax"? I want to understand the ...
5
votes
1answer
83 views
Is there a difference in performance when the symmetry is specified via ibrav in Quantum ESPRESSO?
I have been using cif2cell for converting CIF files into quantum ESPRESSO input files. But cif2cell always keeps the ibrav value to be zero and indicates the CELL_PARAMETERS. As per the quantum ...
13
votes
2answers
154 views
Deciding the number of CPUs for a DFT calculation for band structure in Quantum ESPRESSO?
If I am using Quantum ESPRESSO for bandstructure calculations, how can I know the number of CPUs necessary for such a calculation? I deal mostly with ternary transition metal oxides which have at ...
10
votes
1answer
104 views
How many GB of RAM would be needed for VASP to evaluate optical properties of a material?
Even though it is a powerful tool, Quantum ESPRESSO's hardware requirements are very high. For instance, to evaluate optical properties, even for structures with tens of atoms, Quantum ESPRESSO can ...
6
votes
1answer
137 views
How to choose starting magnetization while doing spin polarised calculation in Quantum ESPRESSO?
I am trying to run spin polarised DFT calculation in Quantum ESPRESSO on system Co2MnSi. I kept starting magnetization for all these three species as,
...
10
votes
1answer
201 views
How to calculate the energy of conduction band and valence band with respect to vacuum in quantum espresso?
I was able to calculate band energies in quantum espresso. How to convert them to values that are in terms of difference from vacuum energy?
9
votes
1answer
68 views
Can you list some useful code snippets for processing quantum ESPRESSO output files?
I know that this is quite general. But we have all written code for processing output files from various dft codes. The functionality of which, may range from analysing time traces to finding ...
8
votes
1answer
140 views
Spin polarized DFT calculation in Quantum ESPRESSO
I am trying to run spin polarized DFT calculation on system Ti2FeSn.
I am doing vc-relax calculation to relax the unit cell but having problem to converge total energy. Total magnetization is also ...
13
votes
2answers
770 views
What is nscf calculation in Quantum ESPRESSO?
I have been using 'nscf' for DOS calculation since it is faster and therefore possible to use a higher kpoints. But why is it faster? why not use it in the place of 'scf'?
8
votes
1answer
105 views
How to model electric field in Quantum ESPRESSO?
I have seen papers that take change in Gibbs Energy by just adding a 'eU' term where U is the potential applied. Is there any better way to do this in Quantum Espresso? And is the former way accurate ...
8
votes
1answer
155 views
How to apply solvent model in Quantum ESPRESSO?
In many cases especially when it comes catalysis (which is what I work in) the effect of solvent comes into effect. I have seen papers that takes into account water as solvent by adding a number of ...
5
votes
1answer
53 views
How to separate the band structure of different materials in heterostructures using Quantum ESPRESSO?
So, I know that to calculate surface band structure of a material, you have to take its 2D system eg. single or few-layered. But, how to find the surface band structure in the case of heterostructures....
9
votes
2answers
365 views
Plotting density of states of Fe(BCC) using Quantum ESPRESSO
I have run the DFT calculation and plotted DOS of Fe(BCC) in Quantum ESPRESSO. I have attached the plot:
(click on image to see clearly)
But It's a wrong plot as it is not matched with the referenced ...
8
votes
1answer
116 views
How to extract the Pressure, Energy and unit-cell volume from quantum ESPRESSO output file using bash script?
I needed the Energy and Volume values for predicting the bulk modulus of a crystal via the Birch Murmaghan equation. Can I get a bash script for doing the same.
5
votes
2answers
65 views
How can I increase the default maximum limit on step size for convergence in quantum ESPRESSO?
When trying to manually optimise the geometry of the crystal, I've faced an issue wherein the code stopped the convergence process after just 100 steps (which was the default maximum). Is there a way ...
6
votes
1answer
224 views
How to use the ev.x tool in Quantum ESPRESSO?
The requirement I have is to calculate the bulk modulus from the Energy values at certain Volumes obtained via DFT calculations. Can you provide the instructions to use the ev.x tool in the Quantum ...
5
votes
1answer
88 views
How to resolve the cif2cell TypeError?
I have encountered an error using cif2cell while covering a CIF file from COD to quantum ESPRESSO format. The error is as follows.
command typed:
$cif2cell crystal.cif -p quantum-espresso -o crystal....
9
votes
1answer
76 views
Quantum ESPRESSO: parameter “assume_isolated”: is it applicable to slabs?
I am studying atomic slabs which are periodic in 2 dimensions. Normally in the third dimension, I add a vacuum layer and use dipole correction to mimic proper boundary conditions. Recently I have ...
7
votes
1answer
356 views
What is the physical meaning of occupations='smearing' in Quantum ESPRESSO?
I want to understand, what is the intuition behind using the occupations='smearing' or 'tetrahedra' in Quantum ESPRESSO input file? I mean how we can interpret what is going to happen inside of ...
10
votes
2answers
170 views
Should I do vc-relax with nspin=2 in Quantum Espresso for magnetic samples?
I'm a beginner when it comes to DFT and Quantum Espresso.
Consider I have a lattice which has associated magnetic properties. So for geometric optimization should I take into account the magnetic ...
8
votes
1answer
63 views
How to predict new Half Metallic materials with higher degree of spin polarization?
Using DFT calculations, how one can predict the new half metallic materials with higher degree of spin polarization. I want to know the steps which have to be followed in prediction of new materials. ...
8
votes
0answers
77 views
Why are the optical properties of Aluminium so hard to determine?
I am trying to determine the optical properties of bulk Aluminium and related alloys using Quantum ESPRESSO. I am using both the epsilon.x and the simple.x modules to get wavelength-dependent ...
