Graphene atoms moving in simulation box

Hello everyone,

I have simulated 252 atoms of graphene and functinonalized graphene with -OH groups. I deformed the simulation box in zigzag direction of graphene with fix deform command. Then I plotted the x,y,z coordinates in MATLAB and found out that my graphene sheet is moving in the simulation box although I am pulling along uniaxial mode. I remapped the atomic coordinated also. I am using PBC in all directions. Here’s a part of my code and MATLAB plot:

Applying axial and shear strain by fix deform

fix 8 all nvt temp {temp} {temp} 5.0 drag 1
fix 9 all deform 1 x erate ${erate1} units box remap x

Is there anything I have to do to keep the atoms fix in the box without using set force 0?

Regards,
Baig

zdisp0-r25.tif (669 KB)

zdispf-r25.tif (664 KB)