LAMMPS has an option to output forces on atoms:

http://lammps.sandia.gov/doc/compute_property_atom.html

Ray

LAMMPS has an option to output forces on atoms:

http://lammps.sandia.gov/doc/compute_property_atom.html

Ray

Hi,

And this force should be averaged on time and space domain through fix ave/spatial.

LAMMPS has an option to output forces on atoms:

http://lammps.sandia.gov/doc/compute_property_atom.html

Ray

Not necessarily. Adhesive force between two slabs is the difference

between sums not averages.

Ray.

Difference between the sums.

Well, as I think the compute property/atom computes the values corresponding to each atoms. On the other hand, in MD simulations there a statistic behavior and we should average in the time and space domains in order to find the real values. Then, we can multiply this value by the number of atoms. May be “fix ave/spatial” is better than the “compute reduce sum” in the way that the first averages on the time and space.

In summery, compute stress/atom and then fix ave/spatial and finally multiplying the output of this fix by the volume of each bin can take the stress.

Am I wrong?

Not necessarily. Adhesive force between two slabs is the difference

between sums not averages.

Ray.

Okay, you did not say you will multiply this averaged value by the

number of atoms. If you don't multiply by the number of atoms, then

it is not correct.

Then what is the difference between "sum of forces on all atoms" and

"average of forces on all atoms multiplied by the number of atoms"?

Same, right? So you can do it both ways.

Ray