# Atoms distortion at periodic boundary for some orientation

Hello Lammps users,
Hi am using Cu system considering different set of planes.
I have taken z as periodic boundary.

lattice fcc 3.6323
# Simulation box

region s_box block 0 450 0 200 -90.8075 90.8075 units box

Z is given dimension as integral multiple of lattice constant.

Now for different planes, at the periodic boundary (Z-axis), atoms are getting distorted except for z plane as 001

lattice fcc 3.6323 orient x 1 1 0 orient y -1 1 0 orient z 0 0 1 — No distortion
lattice fcc 3.6323 orient x 1 0 0 orient y 0 1 0 orient z 0 0 1 ---- No distortion

lattice fcc 3.6323 orient x 1 -1 0 orient y 1 1 1 orient z -1 -1 2 ----- Distortion

lattice fcc 3.6323 orient x -1 1 0 orient y 0 0 1 orient z 1 1 0 ----- Distortion

lattice fcc 3.6323 orient x 1 0 0 orient y 0 1 -1 orient z 0 1 1 ----Distortion

Figures are also attached after carrying out CNA. Kindly provide some solution to avoid mismatch of atoms with periodic images.

Hello Lammps users,
Hi am using Cu system considering different set of planes.
I have taken z as periodic boundary.

*lattice fcc 3.6323 *

*# Simulation box *
*region s_box block 0 450 0 200 -90.8075 90.8075 units box *

Z is given dimension as integral multiple of lattice constant.

​that is not sufficient. depending on the choice of orientation. you may
need to have a multiple of 2, 3 or more lattice constants to have clean
periodic continuation.

axel.​

Right now the z axis is 50 times the lattice constant. the number (90.80752) is also integrally divisible by (23.6323) but not by (3*3.6323) .Which dimension then should be chosen for Z. and on what basis? Pl. throw some light.

Till now I could see that 001 z-plane dimension if integrally divisible by lattice constant, then atoms don’t interfere with periodic images.