Table of Contents

Running MD in VASP basics

This is by no means complete guide to run MD with vasp, more like an example for fcc Fe with 5x5x5 supercell.

INCAR

This involves rather few modifications: we need to tell VASP that we are indeed running MD and we need to use

INCAR
TEBEG  = 3731                       # Starting random velocities, in K
IBRION = 0                          # Ensure that we are running MD
POTIM  = 1.0                        # Timestep in femtoseconds
SMASS  = 0                          # Nose thermostat
 
NSW    = 2000  
 
IALGO   = 48                        # The algorithm used for the SCF iterations
                                    # 38 = Blocked-Davidson algorithm (DAV), default, most stable method.
                                    # 48 = Residual minimization method direct inversion in the iterative subspace (RMM-DIIS), faster then (DAV)
EDIFF  = 1E-4
ISTART = 0                          # Start from scratch, don't use any leftovers from previous runs
NELMIN  = 6                         # Do a minimum of 6 SCF iterations
NELM    = 100                       # Do a maximum of 100 SCF iterations 
 
LCHARG  = .FALSE.                   # Whether or not the charge density output file CHGCAR should be written, often a quite large file. 
LWAVE   = .FALSE.                   # Whether or not the wave function output file WAVECAR should be written, often a quite large file. 

POSCAR

POSCAR
fcc Fe, volume=7.1706 
   3.061052794 
 0.000000000000  2.500000000000  2.500000000000 
 2.500000000000  0.000000000000  2.500000000000 
 2.500000000000  2.500000000000  0.000000000000 
Fe 
125 
direct coordinates
 0.000000000000  0.000000000000  0.000000000000 site: 1
 0.000000000000  0.000000000000  0.200000000000 site: 2
 0.000000000000  0.000000000000  0.400000000000 site: 3
 0.000000000000  0.000000000000  0.600000000000 site: 4
 0.000000000000  0.000000000000  0.800000000000 site: 5
 ...
 0.800000000000  0.800000000000  0.000000000000 site: 121
 0.800000000000  0.800000000000  0.200000000000 site: 122
 0.800000000000  0.800000000000  0.400000000000 site: 123
 0.800000000000  0.800000000000  0.600000000000 site: 124
 0.800000000000  0.800000000000  0.800000000000 site: 125

KPOINTS

Sometimes it is more reasonable to run cheaper calculation more than a heavy calculation for a shorter amount of time.

KPOINTS
Comment
 0
Monkhorst Pack
 1  1  1 
 0  0  0 

POTCAR

Same considerations: sometimes it is more reasonable to choose lighter POTCAR but run the simulation longer than to use a heavy one.

Running VASP

< Add info on running with multiple nodes for more memory and limits >

job
#SBATCH -A liu1
#SBATCH -p green
#SBATCH -J MY_FIRST_RUN
#SBATCH -N 1 
#SBATCH -t 10:00:00
 
cd /path/to/simulation/dir
 
mpprun /software/apps/vasp/5.3.2-13Sep12/default/vasp-half