cd Si relaxation
Based on the VASP wiki example in this link
Task: Relaxation of the internal coordinates of a perturbed cubic diamond Si structure.
System-specific instructions
Select instructions for the system you are using:
Instructions for use on the NAISS cluster Tetralith (NSC)
Instructions for use on the EuroHPC cluster LEONARDO
First, copy the example folder which contains some of the VASP input files and useful scripts
cp -r /software/sse2/tetralith_el9/manual/vasp/training/ws2024/cd_Si_relax .
cd cd_Si_relax
and copy the latest POTCAR file for Si
cp /software/sse2/tetralith_el9/manual/vasp/POTCARs/PBE/2024-03-19/Si/POTCAR .
cp -r /leonardo_scratch/fast/EUHPC_TD02_030/vasp_ws2024/examples/cd_Si_relax .
cd cd_Si_relax
and copy the latest POTCAR file for Si
cp /leonardo_scratch/fast/EUHPC_TD02_030/vasp_ws2024/potpaw_PBE.64/Si/POTCAR .
Input files
POSCAR
cubic diamond Si
5.5
0.0 0.5 0.5
0.5 0.0 0.5
0.5 0.5 0.0
Si
2
Direct
-0.125 -0.125 -0.125
0.125 0.125 0.130
Note the distortion for the 2nd atom in z, from 0.125 to 0.130
INCAR
System = diamond Si
ISTART = 0
ICHARG=2
ENCUT = 240
ISMEAR = 0
SIGMA = 0.1
NSW = 10
IBRION = 2
ISIF = 2
EDIFFG = -0.0001
NSW=10 relaxation steps
IBRION=2, conjugate-gradient algorithm
ISIF=2, relax only internal parameters
KPOINTS
k-points
0
Monkhorst Pack
11 11 11
0 0 0
Calculation
The input files are ready for the atom relaxation, so the job can be directly submitted
sbatch run.sh
Check the progress of the relaxation by e.g.
cat slurm*out
cat OSZICAR
the calculation should be quite fast. At the end of OUTCAR, e.g. using less, check the final forces
POSITION TOTAL-FORCE (eV/Angst)
-----------------------------------------------------------------------------------
4.81938 4.81938 4.81254 -0.000143 -0.000143 -0.001100
0.69437 0.69437 0.68746 0.000143 0.000143 0.001100
-----------------------------------------------------------------------------------
total drift: 0.000001 0.000001 -0.000003