discussed version: 5.4.4 and 6.3.1
Credits: Sergey Matveev and Victor Vysotskiy (installation, scripts), Dmitry Aksenov (guidelines, scripts)
- Follow VASP instructions. Here are our makefiles.
- To generate input files locally unzip pseudopotentials to a desired program folder, I use
Note that individual files may be compressed – decompress them.
- Job submission scripts:
- PBS submission command:
qsub vasp/_pbs -N test1
- SLURM submission command:
sbatch -J test1 -c 16 -t 24:00:00 vasp/_pbs
sbatch -J test1 --ntasks-per-node=16 --mem=32gb vasp/_pbs
- Sample input files: zip
- On some clusters VASP does not recognize INCARS created in Windows, so they should be convereted to UNIX format.
- Electronic density (
CHGCAR file) can be visualized by VESTA program.
- VASP has its own visualization tool: p4vasp.
- To continue interrupted ionic relaxation copy
- In case of
RHOSYG: internal error: stars are not distinct, set
- For linear response
LREAL=F is the only option.
NPAR=1 is probably the best choice for single node shared memory run.
- To remove orbital occupations use this script (run
trimoutcar.sh OUTCAR > OUTCAR_new, thanks to Dmitry Aksenov).
- For calculation of DOS use
ISMEAR=-5 (it might be necessary to converge
WAVECAR by other method).
- For calculation of band structure with hybrid functionals the approach described in VASP-wiki works only for the provided example.
For other cells and finer grids it produces inaccurate eigenvalues at least those with zero weight.
The main challenge is to converge eigenvalues (individual eigenvalues converge much more slowly than band energy).
At the minimum, one has to increase precision (PREC, maybe PRECFOCK) and number of SCF steps (only ALGO D and A are applicable).
- Read VASP documentation: Electronic optimization.
- Look into existing convergent calculations in any internal (
Data folder) or external database (e.g. Materials Project).
- Continue iterations (run VASP with existing
- Start with good
WAVECAR, e.g. from smal energy cutoff. Set
ICHARG=0 otherwise VASP may take wrong charge density.
- Start with good
CHGCAR, e.g. from spin nonpolarized calculations, small k-grid etc.
If needed correct unit cell parameters in
CHGCAR to match
POSCAR otherwise VASP ignores it.
Alternatively you can set the grid appropriately.
- Change algorithm:
ALGO=Fast is reasonable default choice for insulators (KFeSO4F) but only for Gaussian smearing.
- Change density mixing (LiFePO4 by materialsproject).
- Do non-SCF steps:
NELMDL=-9 (usually a number from -6 till -12).
LMIXMAX=4 (or even 6 for f-elements) for LDA-U calculations, see details here.
LSUBROT=T, see details here.
- Try U-ramping. Check occupations by
- Shake geometry and take the lowest energy result.
- On some computing clusters (e.g. Pardus and Arkuda) blocked-Davidson scheme changes number of electrons, so
ALGO=VeryFast seems to be the only option.