Electron Force Field SiO2 example

Dear users,
I’m looking for a minimal example of SiO2 or quartz, with EFF and
the electron mass set on its real value. Indeed, while the examples included in LAMMPS
run smoothly, I found very difficult to obtain a stable cell of SiO2.
In particular I built up the SiO2 cell with 4 elecrons disposed on a tetrahedron
around each oxygen atom and a couple of electrons on each bonds.
Is that the correct location?

Thanks in advance,


Dr Andrea Pedrielli, PhD
European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT*)
Strada delle Tabarelle, 286, I-38123 Villazzano TRENTO (TN)

For this, it would likely be best to email the eFF folks (Andres, etc)
directly to ask if they have a suitable example.
I think eFF is more designed for light elements, not Si, but
they can advise you.


Thank you very much Steve,
I tried to write them last month but I did not obtain any answer, so I am trying other ways… I feel uncomfortable writing to personal email many times. If you know someone of them that I do not bother I will surely contact him. With regard to EFF, with Effective Core Pseudopotential (ECP) should be able to deal with the element up to Silicon, there are indeed various papers by EFF group dealing with for example Silicon Carbide. There is also an example in LAMMPS that runs smoothly. However when I move to SiO2 the system undergoes instabilities… My aim would be to describe the bond breaking within SiO2 matrix under irradiation and I think that the valence electrons will be sufficient for the description of the phenomena at low energy, after thermalization of the system.