Hello,
I am trying combine a pairwise potential with a many-body potential using hybrid/overlay, and I have a general question about how pressure is calculated. For pairwise systems, I assume the pressure is calculated from the virial equation for pressure, summing pairwise forces dot distance, and an analogous form for the many-body potential. But when the two potentials are used together with hybrid/overlay, how is the pressure calculated?
Best,
Jo
Forces and stress components are added.
Forces and stress components are added.
--I am trying combine a pairwise potential with a many-body potential using hybrid/overlay, and I have a general question about how pressure is calculated. For pairwise systems, I assume the pressure is calculated from the virial equation for pressure, summing pairwise forces dot distance, and an analogous form for the many-body potential. But when the two potentials are used together with hybrid/overlay, how is the pressure calculated?
Best,
Jo
Hi Jo.
If you are also asking how the contribution to the virial from the
many-body forces are calculated in LAMMPS, then check out this paper:
https://cfwebprod.sandia.gov/cfdocs/CompResearch/docs/JCPSA613115154107_1.pdf
(The authors of the paper, Aidan and Steve are LAMMPS developers.)
Andrew