Dear users.
i am going to adopt a thick vacuum along z direction and apply periodic boundry conditions along the other direction .my system is a lattice of Ni and the system tempreture is controlling by a Berendsen thermostat.can i use vacuum in lammps and how?
thanks
Dear users.
i am going to adopt a thick vacuum along z direction and apply periodic
boundry conditions along the other direction .my system is a lattice of Ni
and the system tempreture is controlling by a Berendsen thermostat.
can i use vacuum in lammps and how?
have a look at: http://lammps.sandia.gov/doc/boundary.html
or search the web for the source code to the "fix uhv/pump" 
axel.
Here is a LAMMPS MD simulation of an infinite and pure vacuum. It is
very efficient and pretty accurate:
[vac] cat > in\.vacuum
atom\_modify sort 0 0
region box block 0 1 0 1 0 1
create\_box 1 box
mass 1 1\.0
run 100
\[vac\] $LAMMPS/src/lmp_mac_mpi < in.vacuum
LAMMPS (30 Sep 2013)
Created orthogonal box = (0 0 0) to (1 1 1)
1 by 1 by 1 MPI processor grid
WARNING: No fixes defined, atoms won't move (../verlet.cpp:54)
Setting up run ...
Memory usage per processor = 0.0463982 Mbytes
Step Temp E_pair E_mol TotEng Press
0 0 0 0 0 0
100 0 0 0 0 0
Loop time of 3.69549e-05 on 1 procs for 100 steps with 0 atoms
Pair time (\) = 0 \(0\)
Neigh time \() = 0 (0)
Comm time (\) = 1\.3113e\-05 \(35\.4839\)
Outpt time \() = 5.96046e-06 (16.129)
Other time (%) = 1.78814e-05 (48.3871)
Nlocal: 0 ave 0 max 0 min
Histogram: 1 0 0 0 0 0 0 0 0 0
Nghost: 0 ave 0 max 0 min
Histogram: 1 0 0 0 0 0 0 0 0 0
Neighs: 0 ave 0 max 0 min
Histogram: 1 0 0 0 0 0 0 0 0 0
Total # of neighbors = 0
Neighbor list builds = 0
Dangerous builds = 0