Questions tagged [vasp]
Questions about or related to the Vienna ab-initio Simulation Package (VASP).
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Free energy calculation
I want to plot the relationship between free energy and temperature. I want to consider two plots, when phonons are considered and when phonons are not considered how the free energy changes with ...
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Wrong lattice parameter of CeO2 after structure relaxation with VASP
I am calculating the lattice parameter of CeO2 with VASP, but the optimized lattice parameter is wrong according to many references (Physical Review B 75, 035109 (2007); The Journal of Chemical ...
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Random velocity generation
How to generate random velocities in the geometry coordinates of a surface (POSCAR file) using the Boltzmann distribution law with Atomic Simulation Environment (ASE) or other codes for Molecular ...
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The Appearance of Imaginary Frequencies in Lattice Vibration Calculations with Increasing KPOINTS
I have been conducting lattice vibration calculations using the Density Functional Perturbation Theory (DFPT) method. While investigating the convergence behavior, I noticed that when I increase the ...
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Absorption enthaply at different temprature in VASP software via ab initio molecular dynamics
Can we calculate the absorption enthalpy at different temperature in VASP software via ab initio molecular dynamics? If yes, how?
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How to perform atomistic spin dynamics (ASD) Ab Initio Molecular Dynamics (AIMD) using VASP?
I have tried normal AIMD simulation using VASP for Non magnetic materials. Now, I am interested to perform the molecular dynamics simulations for the finite temperature for Magnetic materials to ...
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VASP - DOS and band structure with different bandgap (PBE and PBE+SOC)
I did some calculations for the bulk of t-Tellurium, and got some strange results. I calculated the bandgap using the outputs of the SCF calculations and the band gap (~0.5 eV) corresponded with other ...
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Non-analytical correction for dielectric constant calculation in VASP
I am calculating the static (low-frequency) dielectric constant for a polar material in VASP.
Due to the LO-TO splitting, I need to apply a non-analytical correction. My question is how to do this ...
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How to get energy gap change at specific high symmetry points during ab initio molecular simulations？
I want to check the energy gap change during finite temperature ab initio molecular simulations. The results may look like this picture:
How can set aimd simulation to get this result in VASP?
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Fitting of Brich-Murnaghan equation of state
After performing high-pressure calculations for my ABO4 compounds using the VASP software, I am now interested in fitting the Birch-Murnaghan equation of state to either pressure versus volume or ...
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Can the the relaxed energy of a material system (eV/atom) computed by DFT using VASP be positive?
If it is positive, why is it so? Is it due to specific convergence criteria or choice of pseudopotentials? I cannot check the convergence of the DFT calculations as they have been downloaded from a ...
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Adsorption of Li on GeC (optimization problem)
Actually I am trying to study the adsorption of Li or K on the sheet starting from the hexagon centre the system optimises with Li or (K) adsorbed over one of the Ge atoms and not remain at the centre....
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Noise in VASP Band Structure Generation with SOC
What could be the reason behind encountering noise at the starting point while using VASP with SOC for generating a band structure? Despite attempting various approaches such as increasing line ...
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Discrepancy between Force Convergence in Geometrical Optimization and SCF Calculation in VASP: Reasons and Troubleshooting Suggestions
During a geometrical optimization of ions and lattice parameters in VASP, the forces acting on atoms were minimized to less than 0.01 eV/Å. However, when performing the subsequent self-consistent ...
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Can the electron charge density of two material systems be similar?
Broadly given two electron charge density (ECD) fields, is it possible to distinguish between the elements present in both the systems?
Since the ECD does not explicitly present any information on the ...
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How to set the LMAXMIX tag in VASP for the material BaLaMn2O6?
I am trying to do DFT+U calculation for the material BaLaMn2O6 . As per the vaspwiki it is recommended to set LMAXMIX = 4 (d-elements) and ...
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Optimal choice between ISIF = 3 and ISIF = 4 for lattice parameter and atomic position relaxation in VASP calculations
In my VASP calculations, I am interested in simultaneously optimizing both the lattice parameters and atomic positions of my system.
I understand that using ISIF = 3 allows for relaxation of both ...
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How do I calculate XPS spectra for molecules to match experimental spectra?
I am trying to calculate the XPS spectra using the ICORELEVEL method in VASP, both using initial and final state approaches, for C1s and F1s electrons. My systems are single molecules.
However, my ...
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What key considerations should be kept in mind when creating a VASP POSCAR file?
What factors can cause convergence issues in VASP calculations and how can they be avoided when creating the POSCAR file? Additionally, could you provide information about the recommended number of ...
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HSE06 - dos + band structure calculation using VASP
I'm a little confused with the order and flags needed to start the calculation with HSE06. Below is a step-by-step guide to what I've done so far.
Obs: I use GGA
For DOS
Step (I) - Structure ...
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What is the best model to calculate the free energies using ASE thermochemistry?
I am trying to calculate the free energy of adsorption of a small molecule on a 2D material. After adsorption, I am using the thermochemistry module of the Atomic Simulation Environment to calculate ...
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Can adsorption energy be upto -8 eV for VOC adsorption in MoS2 layer?
I've been using VASP for DFT calculations and came across with an adsorption energy value over $-8\,eV$.
Is this a reasonable value for S-H bond?
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What do we get by integrating over the charge density data of a material system calculated with DFT?
I am confused as to whether integrating over the charge density gets us the number of valence electrons in the material system or the total number of valence electrons in the material system.
Let's ...
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How may I calculate atomic orbital energies using VASP?
I am trying to calculate the d orbital energy of the Cu single atom, like in this page, I have tried to use the Eigenband energies minus the vacuum energy level(about 0.007eV).
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My INCAR file, POSCAR, and KPOINTS are same for GGA, however after the PBE calculation, I found that the bandgap is Changing. Why is that happened?
INCAR, POSCAR, and KPOINTS are the same but for the same calculation, the bandgap is changing.
First, I relaxed the structure then did the self-consistent calculation, and bandstructure calculation. ...
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Modeling techniques for simulating the electronic and structural properties of Transition Metal Dichalcogenide nanotubes
Dear Matter Modeling Stack Exchange community,
I am currently working on calculating the electronic and structural properties of Transition Metal Dichalcogenide (TMD) nanotubes using DFT, with a ...
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Does VASP include energy penalty contribution in OUTCAR energy of constrained moment calculation?
In VASP, one can use I_CONSTRAINED_M to constrain local magnetic moments to a certain direction in SOC calculations. However, this comes at the cost of adding an energy penalty to the total energy. ...
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Are then any material property solvers (from Charge Density) available in python?
I am looking to predict properties like the Bulk Modulus, total energy, etc., all from the charge density I have as input (CHGCAR file)
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Clarifying local magnetic moment axes in VASP: cartesian vs crystal (for MAGMOM/M_CONSTR)
In VASP, one can set the local magnetic moments of each ion in a non-collinear SOC calculation along a certain direction using the MAGMOM/M_CONSTR tags. The manual linked to states that these local ...
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How to calculate anisotropic exchange J $J_{xy}, J_{xz}, J_{yz}, J_{yx}, ...$ using 4-state mapping and DFT?
In this review, the authors present several schemes to calculate various quantities like single-ion anisotropy, DMI, and anisotropic exchange J using DFT. For instance, the DMI term in the y-direction ...
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Why dipole correction does not work in VASP DFPT + phonopy calculation for a stable 2D material
Seems that DFPT method in VASP has many defects. It can't include vdw interaction. Now I found it also can't include dipole correction, which leads to a large negative frequency at $\Gamma$ point. I ...
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How can I maximize both CPU and GPU usage when running OpenACC VASP?
I am currently running a fairly large system (NELECT>7400) on the OpenACC GPU port of VASP 6.4.1 on 16 Nvidia A100 GPUs: 4 GPUs x 4 nodes (NCSA Delta 4-Way NVIDIA A100 GPU Compute Nodes). Each of ...
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Error correction software for VASP calculations
I am looking for error correction packages for VASP calculations that can be integrated into a high-throughput worfklow. Ideally the software would both find and propose fixes for errors at runtime, ...
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Contents of a CHGCAR file and how to read it appropriately in Python? [duplicate]
Rephrasing the above, what is the content of the data in the CHGCAR file?
Is the data part shown below representative of the electron-charge density or is it the actual charge in the system and I have ...
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Is it necessary to use DFT+U when calculating binding energy?
Recently I am trying to calculate the binding energy between CO2/ C2H2 and MOF (containing Ni, C, H, O, N).
I want to know that do I have to use DFT+U for Ni element in this binding energy calculation?...
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When calculating DOS and band structures, do I still need to provide a regular mesh for MetaGGA functionals as in the case with hybrid functionals?
In VASP manual it is mentioned that the deorbitalized versions of SCAN and R2SCAN MetaGGA functionals do not depend on the kinetic energy density but instead on the Laplacian of the charge density.
...
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How to get displacements along VASP NEB trajectory?
I am performing an NEB calculation with VASP and VTST. I would like to visualize the atoms along the path and to calculate their displacements. When I have a single relaxation's XDATCAR, I can unwrap ...
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Calculation of charge defect formation energy
I am confused about the calculation of the charge defect formation energy equation with these two terms (from figure below):
$\Delta V$: alignment term, and
$E_{corr}$: correlation term.
How can I ...
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Which is better? Rashba effect or Dresselhaus effect?
My current research focus is on the band splitting observed in 2D perovskite. Existing literature suggests that site inversion asymmetry (SIA) may lead to the Rashba effect, while bulk inversion ...
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Query about NiO structure
I have one query about the NiO structure. As per the literature, NiO is a rocksalt type of structure ( NaCl type) and exhibits an antiferromagnetic ordering of type-II cubic (fcc). I considered the ...
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Fix layers of a slab
How do you fix the bottom layers of a slab to mimic a bulk material in ASE? Any functional that takes the slab object and writes a POSCAR with selective dynamics will be deeply appreciated. Thank you.
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Issue with py4vasp and Jupyter Lab Integration on Windows 10?
I am currently working on a project involving py4vasp for crystal structure analysis. I have successfully installed py4vasp, Jupyter Lab, and Jupyter Notebook in a Conda environment. When I attempt to ...
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Why the total energy calculated with GGA and metaGGA=SCAN are so different?
Why the total energy calculated with GGA and metaGGA=SCAN are so different?
My INNCAR file is
...
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How to estimate the minimal distance between atoms for which a pseudopotential-based AIMD gets forces correctly?
I am doing ab initio molecular dynamics in VASP. As far as I know, pseudopotentials approximate all-electron potential far from the nucleus, and deviate from it near the nucleus.
When some of my atoms ...
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VASP jobs crashing - VASP 5.4.4
I have been trying to generate potential energy curves with doing single point calculations with VASP - 5.4.4
many of my jobs crash or stay stuck on a single line until it runs out of time. can some ...
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How to set G-type AFM and U parameters in VASP when optimizing structure?
I am trying to reproduce results from research. In computation details part, it mentioned some setting about G-type AFM and Hubbard parameter:
1.
A Hubbard parameter (U) of 5 eV was used to treat the ...
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Proper workflow for VASP
Could someone tell me what the optimal workflow to study the various properties of a material is? I am new to using VASP and would like to know what order I should run the calculations and what are ...
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How do we calculate thermodynamic properites using VASP 6.1.0?
How do we calculate thermodynamic properties using VASP 6.1.0?
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Helmholtz vibrational energy from VASP calculations
I would like to calculate the Helmholtz vibrational energy. I have done the phonon calculations. My question is how to extract the vibrational energy from the output of the Vasp calculation.
A source ...
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How to integrate CHGCAR data of VASP, in z-direction and have xy-plane charge density at each grid point on xy-plane?
i asked this query in another forum, waiting for answer. However, also posting it here.
i got a CHGCAR file written for both optimised and non-optimised (single point run) runs of a lattice model.
So, ...
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