Help with Gamma Alumina

LAMMPS LAMMPS General Discussion
1

Hi everyone,

I’m trying to simulate gamma alumina (γ-Al₂O₃) in LAMMPS, but I’m facing challenges setting up the correct structure and potential. Based on what I know so far:

  1. Gamma alumina has a defective spinel structure with both tetrahedral and octahedral coordination for aluminum atoms, along with vacancies. I need to ensure the right Alratio (2:3) and the appropriate atomic positions and coordination.
  2. For the interatomic potential, I plan to use the Buckingham + Coulombic interactions. I’ve seen parameters for Al-O and O-O interactions used in other alumina systems, but I’m not sure if they’re fully appropriate for gamma alumina, which has more structural disorder. Should I be using ReaxFF or stick to Buckingham?
  3. I also want to ensure I’m assigning the right charges. Currently, I’m setting Al³⁺ to +3.0 and O²⁻ to -2.0. Does anyone have recommendations for charge assignment based on their experience with γ-Al₂O₃?
  4. Lastly, I’d appreciate any advice on validating my model. I plan to compare lattice parameters, RDFs, and possibly elastic constants with experimental data, but if anyone has tips for γ-Al₂O₃ validation, that would be really helpful.
2

All the questions you are asking are questions about your research project and not questions about LAMMPS. This is a forum where we answer questions about LAMMPS and not discuss how you should do your research with you. That is the job of your adviser and yourself.
Thus please come back when you have real LAMMPS questions.

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