How to do lattice optimization, encut optimization and Kpoint optimization in VASP?

Question

What is the procedure to do lattice optimization, encut optimization and kpoint optimization in VASP?

Thank you in advance.

Answer 1

You can start with this bash script for Aluminum to begin

Note: Make sure to fix two quantities while changing third one among INCAR,KPOINTS,POSCAR

Lattice optimization

for i in `seq -w 4.01 0.01 4.05` # change the range needed
do
cat <<EOF >POSCAR
Al bulk FCC
$i
0 0.5 0.5
0.5 0 0.5
0.5 0.5 0
1
direct
0.0    0.0     0.0
EOF
mkdir $i
cp INCAR $i/
cp POSCAR $i/
cp POTCAR $i/
cp KPOINTS $i/
cd $i
/apps/VASP/vasp.6.2.0/original/bin/vasp_std  # This is vasp run command add mpi if needed
# post process 
E=`grep 'F' OSZICAR|tail -n 1 | awk '{ print $5}'`;
echo $i $E >>../pos-conv.txt
cd ..
done

Encut optimization

for i in `seq -w 300 50 500` # change the range needed
do
cat <<EOF >INCAR
SYSTEM = Al :fcc
ISTART=0         # start new job
ICHARG=2         # 2 for atom
INIWAV=1         # initial wave function
ENCUT= $i eV # Energy cut-off for calculation
PREC = Normal    # Normal Precision
LREAL= .FALSE    # real space projection .FALSE.
LCHARGE= .FALSE  # no charge file output
LWAVE= .FALSE    # no wavefile output
NCORE=4          # NCORE specifies how many cores store one orbital
ISMEAR = 1;     # smearing
SIGMA = 0.2      # smearing value
ISIF = 2;        # 2- scf CALCULATION/IONIC MOVEMENT # 3 for volume relax
IBRION=2         # cg
NELM=30         # Maximum number of iteration
NELMIN=3         # Minimum number of iteration
NSW=30           # number of step for ionic update
EDIFF=1E-5       # stopping criteria for electronic update
EDIFFG=-0.01     # force convergence
EOF

mkdir $i
cp INCAR $i/
cp POSCAR $i/
cp POTCAR $i/
cp KPOINTS $i/
cd $i
/apps/VASP/vasp.6.2.0/original/bin/vasp_std  # This is vasp run command add mpi if needed
# post process 
E=`grep 'F' OSZICAR|tail -n 1 | awk '{ print $5}'`;
echo $i $E >>../incar-conv.txt
cd ..
done

KPOINTS optimization

for i in `seq  1 1 5` # change the range needed
do
cat <<EOF >KPOINTS
MONK #header file
0
M
$i $i $i
0 0 0
EOF
mkdir $i
cp INCAR $i/
cp POSCAR $i/
cp POTCAR $i/
cp KPOINTS $i/
cd $i
/apps/VASP/vasp.6.2.0/original/bin/vasp_std  # This is vasp run command add mpi if needed
# post process 
E=`grep 'F' OSZICAR|tail -n 1 | awk '{ print $5}'`;
echo $i $E >>../kconv.txt
cd ..
done