I am looking for an efficient interatomic potential to couple with my amorphous silica structure.
I found a couple of papers that seemed helpful.
How do I translate the parameters into one readable in lammps?
I’ve attached the paper with this mail.
It would be helpful if I could get inputs on how to pick out the necessary parameters from the file and use them in the LAMMPS format.
Besides, anyone using any other tested interatomic potential for bulk amorphous silica?
Empirical Three-Body Potential for Vitreous Silica -Garofalini.pdf (840 KB)
To the best of my knowledge, it is not yet possible to run the Feuston/Garofalini potential in LAMMPS because it has a three body interaction that depends not only on the angle between the atoms involved but also on the radii of the relevant bonded atoms. Thus, one needs to maintain a dynamically updated list of three body interactions (and, of course, apply the proper form to each triplet to compute relevant energy/forces). Again to the best of my knowledge, there is nothing preventing one from implementing this potential in LAMMPS; in fact, the modified BMH part may be easily implemented with modifications to code that currently implements:
The F/G potential is attractive because it is a computationally simple - yet reactive - potential and I believe it has been parameterized to allow one to address water reacting with amorphous silica. If you pursue implementing this potential in LAMMPS, please keep me abreast of your progress.
That said, an alternate potential to consider employing is the one due to van Beest, Kramer, and van Santen – the so called, BKS potential. You can look at the following for details:
Phys Rev B, vol 43, p. 5068 (1991)
also see references therein. Put simply, I think you can implement this using either the buck/coul/cut or buck/coul/long pair style. I’m uncertain which but, if you read the relevant refs and LAMMPS doc pages, you should be able to figure this out.
You may also want to take a look at the following from Goddard’s group:
This is a straightforward pair potential and should be “easy” to implement. Alternatively, you can investigate the REAXX force field for silica – I believe one exists but I am a bit clueless beyond that.
Best of luck,
Ed is correct - someone will need to implement a 3-body potential
like FG in LAMMPS. You can use the other 3-body potentials (SW
and Tersoff) as starting points.