Dear all,

I now need to get the interaction force between two groups of atoms. The potential I use is MEAM, including embedding energy part.

Based on the documentation, ‘Compute group/group’ commend can only handle pairwise part, am I right?

Does anyone have good way to handle this force calculation? Any suggestion is highly appreciated!

Thanks for your help!

Best

Ian

What does the force between 2 groups of atoms

mean for a multi-body potential like MEAM? I don't

think it is a well-defined quantity.

Steve

Hi, Steve,

sorry, i may not state my problem very well. I have Al/Si system described by MEAM and a Al bulk compressed by a Si indenter. Now I want to get the force between the Si indenter and Al bulk. How can I obtained them?

Thanks a lot!

Best

Ian

Again, if there are Si indenter atoms interacting with Al bulk atoms

via MEAM, there are a variety of many-body interactions that

MEAM computes. How to bookkeep which force comes from

which atom in a many-body interaction is not clear at all and

LAMMPS doesn't attempt it.

You could just sum up the total force on all bulk (or indenter) atoms.

Since force between bulk atoms will presumably sum to zero, then

the net force would be from the indenter? You can sum per-atom

force over a group with the compute reduce command.

You would have to subtract out any boundary forces you impose.

Steve

Hi, Steve,

Yeah, Thanks for your explanation. I will try the way you suggest.

Best

Ian