Hi:
I am trying to compute the energy of a cubic ZrO2 single crystal under NPT
conditions. I used the press/berendsen command according to the following
script:
units metal
atom_style charge
atom_modify map array
neighbor 0.3 bin
neigh_modify delay 0 every 20 check no
boundary p p p
lattice custom 5.129 orient x 1 0 0 orient y 0 1 0 orient z 0 0 1 &
basis 0.0 0.0 0.0 basis 0.25 0.25 0.25 &
basis 0.75 0.75 0.25 basis 0.75 0.25 0.75 basis 0.25 0.75 0.75 &
basis 0.25 0.25 0.75 basis 0.75 0.75 0.75 basis 0.25 0.75 0.25 &
basis 0.75 0.25 0.25 basis 0.0 0.5 0.5 basis 0.5 0.0 0.5 &
basis 0.5 0.5 0.0
region caja block -2 2 -2 2 -5 5
create_box 2 caja
region grano block -2 1.9 -2 1.9 -5 4.9
create_atoms 2 region grano basis 1 1 basis 10 1 basis 11 1 basis 12 1 &
basis 2 2 basis 3 2 basis 4 2 basis 5 2 basis 6 2 basis 7 2 &
basis 8 2 basis 9 2
group zirconium type 1
group oxygen type 2
mass 1 91.22
mass 2 15.99
set group zirconium charge 4
set group oxygen charge -2
velocity all create 900.0 87287 mom no dist gaussian
pair_style buck/coul/long 4.0 10.0
pair_modify shift yes
pair_coeff 1 1 0.0 10.0 0.0
pair_coeff 2 2 9547.96 0.2192 32.0 # Minervini
pair_coeff 1 2 1502.11 0.3477 5.1 # Idem
kspace_style ewald 1.0e-4
minimize 1.0e-6 0.0 5000 10000
write_restart restart.bulk
fix 1 all temp/berendsen 900.0 900.0 0.1
fix 2 all press/berendsen iso 3000.0 3000.0 10.0
fix 3 all nve
dump 1 all atom 1000 dump.bulk.900_K
thermo_style custom step temp ke pe etotal press vol
thermo_modify lost warn norm yes
thermo 1000
run 200000
The output screen is as follows:
LAMMPS (15 Jan 2010)
Lattice spacing in x,y,z = 5.129 5.129 5.129
Created orthogonal box = (-10.258 -10.258 -25.645) to (10.258 10.258 25.645)
1 by 1 by 2 processor grid
Created 1920 atoms
640 atoms in group zirconium
1280 atoms in group oxygen
640 settings made for charge
1280 settings made for charge
Ewald initialization ...
G vector = 0.273155
vectors: actual 1d max = 845 13 9841
Memory usage per processor = 16.8243 Mbytes
Step Temp E_pair E_mol TotEng Press
0 900 -71133.646 0 -70910.401 -39394.079
1 900 -71133.646 0 -70910.401 -39394.079
Loop time of 0.0927451 on 2 procs for 1 steps with 1920 atoms
Minimization stats:
Stopping criterion = energy tolerance
Energy initial, next-to-last, final =
-71133.646389 -71133.646389 -71133.646389
Force two-norm initial, final = 5.35275e-12 6.87414e-10
Force max component initial, final = 3.82028e-13 4.84093e-11
Final line search alpha, max atom move = 1 4.84093e-11
Iterations, force evaluations = 1 1
Pair time (\) = 0\.0608647 \(65\.6257\)
Kspce time \() = 0.030176 (32.5365)
Neigh time (\) = 0 \(0\)
Comm time \() = 0.00145247 (1.56609)
Outpt time (\) = 0 \(0\)
Other time \() = 0.000251991 (0.271703)
Nlocal: 960 ave 960 max 960 min
Histogram: 2 0 0 0 0 0 0 0 0 0
Nghost: 6394 ave 6394 max 6394 min
Histogram: 2 0 0 0 0 0 0 0 0 0
Neighs: 193920 ave 197566 max 190274 min
Histogram: 1 0 0 0 0 0 0 0 0 1
Total # of neighbors = 387840
Ave neighs/atom = 202
Neighbor list builds = 0
Dangerous builds = 0
ERROR: Illegal fix press/berendsen command
I cannot understand what is the problem with the fix press/berendsen
command. Any help?
Thanks in advance!
Juan J. Meléndez Martínez
Profesor Titular de Universidad
Departamento de Física
Universidad de Extremadura
Avda. de Elvas, s/n 06006 Badajoz (España)
Tfno.: 924 28 96 55
Fax: 924 28 96 51
e-mail: [email protected]