Is there any existing calculator able in ASE to compute energy and forces from point charges on atoms (for periodic system) ? I belive there was one coled ewald.py but it was deleted from distribution. I would like to combine it with MACE, becouse it does not work well with ionic organic crystals.
I’ve also been looking out for such a thing. It would be lovely if there was something that does for Ewald sums what simple-dftd3 does for dispersion.
It would be useful to combine with MLIPs and other short-range models such as phonon force constants.
After some search I was able to find this
The scripts contains ewald.py code calculating electrostatic lattice energy (correctly, checked by me). It can be a good starting point.
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That looks like a handy starting point! But I think it is fixed to work in vacuum, and doesn’t allow for anisotropic charge screening?
A more complete treatment is shown here in the context of defect energy corrections, but it would be nice to find a source that also shows the application to Forces and Hessian. https://journals.aps.org/prb/abstract/10.1103/PhysRevB.87.094111
The code mentioned by me is designed for periodic system, not for vacuum. But it does not compute forces and Hessian. Fortran implementation can be found in GULP source code, but porting to ASE is behind my know how.