sliding atom with AFM spring

Dear users,

I have been trying to move my graphene group with AFM tip using fix
spring command. Actually, I can not use fix smd command because my
executable is a little bit old. Also, I am not permitted to have a new
executable right now.

When I use the in file, no movement occurs for the group attached to AFM tip.

I am deeply appreciate any comment.



Why are you using fix spring for moving a group of atoms? Try use fix move instead.

Also, what is preventing you from updating your own LAMMPS executable?


Dear Ray,

Thanks for your reply.As you suggest, we have a new executable now. Before all calculations, I have minimized my structure.
I have been using fix smd command because I want my mobile group (graphene) to be drifted by an AFM tip to the parallel to top graphite surface . Here, AFM tip is simulated with springs attached to graphene atoms with a certain spring constant. I have achieved to move graphene attached to AFM tip in the z direction during simulation run. Also to simulate loading of an AFM tip, I have loaded all graphene atoms with a certain load force.

Now, the problem is that I can not succeed to move my graphene in the x direction only. However, I have tried to change the direction of the given velocity.But no luck.
Do you think that should I change the direction of the tethering of AFM tip while also changing the velocity direction?
I am deeply appreciate any comments.