Skip to main content
14 votes
Accepted

Density of States of Supercells

The density of states reads: $$ \tag{1} g(E)=\sum_{n}\int\frac{d\mathbf{k}}{(2\pi)^3}\delta(E-E_{n\mathbf{k}}), $$ where $E_{n\mathbf{k}}$ are the electronic energies and the integral is over the ...
ProfM's user avatar
  • 11.1k
13 votes

Moving from VASP to CASTEP for bulk crystal and surface calculations

As the answer above mentioned, the biggest difference is perhaps CASTEP takes two input files with suffix "cell" and "param", other things are very similar. After all, both ...
bzbzbz's user avatar
  • 721
12 votes
Accepted

Moving from VASP to CASTEP for bulk crystal and surface calculations

The workflow transferring from VASP to CASTEP is quite similar. Within VASP, there are four main files that you need for a calculation: POSCAR – gives the positions of the atoms within the unit cell ...
benshi97's user avatar
  • 418
10 votes

Which output file from CASTEP after geometry optimization is like with the CONTCAR from VASP?

The main structural output of a geometry optimization in Castep is in the file with the ".geom" extension. That file contains blocks with lattice parameters and atomic positions at each step ...
ProfM's user avatar
  • 11.1k
8 votes
Accepted

Comprehensive tutorial for CASTEP without Material Studio Visualizer

I'll try to write a longer answer when I have more time, but the best place to start is the CASTEP documentation site: https://castep-docs.github.io/castep-docs/ which contains tutorials for all the ...
Phil Hasnip's user avatar
  • 8,052
8 votes
Accepted

HSE06 Starting Guess

Yes, you can do this. First, do a normal PBE calculation (HSE is built on-top of PBE) which generates an <seed>.check and ...
bzbzbz's user avatar
  • 721
6 votes

Which output file from CASTEP after geometry optimization is like with the CONTCAR from VASP?

As mentioned by @ProfM, you can use the last step of the .geom file. Additionally, a particularly helpful parameter that I use is write_cell_structure. If set to ...
Ava's user avatar
  • 61
6 votes

Adjusting y-axis of CASTEP band structure plots

Yes. xmgrace allows you to do arithmetic on datasets. To shift the minimum of the bands to zero, you need to do the following steps. Find the maximum of the valence band along the y-axis (the VBM). ...
Keith Refson's user avatar
5 votes
Accepted

Help with Geometry Optimization in CASTEP

If you are running only geometry optimization for a single crystal periodic structure, the third step: (3) Build unit cell > geometry optimization > band structure and optical calculation will ...
Camps's user avatar
  • 23.6k
4 votes
Accepted

optical properties in IR region

Let's start by putting aside the DFT for a moment and consider the experimental system. That has a bandgap of ~ 4 eV (i.e. somewhere in the UV -- the precise number is irrelevant to the discussion!). ...
Robert Lawrence's user avatar
4 votes

Calculate IR refractive index (NK)

Yes,I think this is possible within CASTEP. I presume that you have run the "efield" or "spectral" task to extract the electronic contribution to the dielectric function, and that ...
Robert Lawrence's user avatar
4 votes
Accepted

Errors in CASTEP supercell geometry optimization

The error message says that the computer did not have enough memory to perform the calculation (line 2 of the log you photographed). You don't give any details about your calculation, but in general ...
Phil Hasnip's user avatar
  • 8,052
3 votes

CASTEP: Tools for extracting .castep output into OriginLab or similar programs for plotting

I have used CASTEP a lot, through the Materials Studio suite though. Initially, I was doing everything manually, but as you mentioned, it is a very tedious task. I ended up writing my own codes to ...
Oscar Lopez's user avatar
3 votes

CASTEP Spectral Bandstructure Tasks

These input param files both compute the same thing (the bandstructure or DOS, depending on the k-point set you provide) but the "spectral" route uses the ...
Phil Hasnip's user avatar
  • 8,052
3 votes
Accepted

An intuitive GUI for CASTEP instead of Material Studio Visualizer

Since you seem to be able to construct and visualise molecules and crystal structures fine (with Avogadro, Vesta etc.) I will assume that you're really asking about the simulation parameters, rather ...
Phil Hasnip's user avatar
  • 8,052
2 votes

CASTEP: specification of uniform pressure in a non-orthogonal unit cell?

For an isotropic (hydrostatic) pressure, you would expect that to give you a diagonal matrix, so: ...
Robert Lawrence's user avatar
2 votes

Which output file from CASTEP after geometry optimization is like with the CONTCAR from VASP?

Others have explained how to get the information from CASTEP, and you could probably also use ASE to convert the files for you, but do you really need to generate a CONTCAR? Most tools I know accept ...
Phil Hasnip's user avatar
  • 8,052
2 votes

How to add a break into CASTEP k-point path

Your .cell file is correct, and CASTEP has added a break between the k-point path for the spectral kpoints; for example, there are no spectral k-points between the ...
Phil Hasnip's user avatar
  • 8,052
2 votes

CASTEP: Tools for extracting .castep output into OriginLab or similar programs for plotting

This is a somewhat delayed response but I hope that this is better late than never. The answer to the immediate use case for data extraction for convergence testing is addressed by the CASTEPconv ...
Keith Refson's user avatar
1 vote

How to add a break into CASTEP k-point path

I have an updated version of the dispersion.pl script which detects and correctly handles breaks in the path. This may be downloaded from https://github.com/krefson/...
Keith Refson's user avatar

Only top scored, non community-wiki answers of a minimum length are eligible