[lammps-users] about rigid!

Dear support, in my problem I have
a) a top substrate
b) a lubricant
c) a bottom substrate

I use the command fix aveforce on the top atom and these atom are rigid but when I apply a force in order to measure the friction property the atom in the top does not move as a rigid body but like a snake. There is a kind of shake command that constraint the distance between atoms?

Regards.

Nicola

Your question is unclear to me. No one
will want to debug your input script, so you
need to narrow down the problem to what
doesn't work the way you expect.

Steve