H2O molecular dynamics
- INCAR
PREC = Normal ! standard precision ENMAX = 400 ! cutoff should be set manually ISMEAR = 0 ; SIGMA = 0.1 ISYM = 0 ! strongly recommended for MD IBRION = 0 ! molecular dynamics NSW = 100 ! 100 steps POTIM = 1.0 ! timestep 1 fs SMASS = -3 ! Nose Hoover thermostat TEBEG = 2000 ; TEEND = 2000 ! temperature
- KPOINTS
Gamma-point only 1 ! one k-point rec ! in units of the reciprocal lattice vector 0 0 0 1 ! 3 coordinates and weight
- POSCAR
H2O _2
0.52918 ! scaling parameter
12 0 0
0 12 0
0 0 12
1 2
select
cart
0.00 0.00 0.00 T T F
1.10 -1.43 0.00 T T F
1.10 1.43 0.00 T T F
the pair correlation function can be visualized using e.g. the following script:
- plot_PCDAT
awk <PCDAT >PCDAT.xy '
NR==8 { pcskal=$1}
NR==9 { pcfein=$1}
NR>=13 {
line=line+1
if (line==257) {
print " "
line=0
}
else
print (line-0.5)*pcfein/pcskal,$1
}
'
cat >plotfile<<!
# set term postscript enhanced colour lw 2 "Helvetica" 20
# set output "pair_correlation.eps"
set title "pair-correlation of H2O at 2000 K"
set xlabel "r [Angstrom]"
set ylabel "g(r)"
plot [0:15] "PCDAT.xy" w lines
!
gnuplot -persist plotfile
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