How to keep layers constant in lammps

Dear Ali,

You can do time integration for only layers you want or you can treat them as frozen layers as

You can think of using fix rigid command too, it depends on what you want to do.

Hi,

I am calculating surface energy for gold surface (Au520), I have
gernerated a slab of 14 layers,now want to perform optimization for the
topmost half layers by keeping rest of them constant so they act like bulk,
but dont know how to do?

4 comments:

  • it is bad wording to talk about “constant” atoms. it would be better to
    talk about “immobilized” atoms or “frozen coordinates”.
  • if you don’t know how to do something, you should first spend some time
    researching this. the question you are asking is one of the most frequently
    asked question on this mailing list and it has been answered many, many
    times. the next time, you before you ask a question like this, please have
    the courtesy to search the manual and the mailing list archives.
  • have a look at fix setforce
  • having 7 immobile layers seems excessive. what kind of gold potential are
    you using? have you checked what effective cutoff it has? you may be
    wasting computer time.

Dear Ali,

You can do time integration for only layers you want or you can treat them
as frozen layers as

You can think of using fix rigid command too, it depends on what you want
to do.

​no. this is not correct. neither of those options works for minimization.

axel.​