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Interatomic Potentials

amorphouspy provides built-in support for classical interatomic potentials widely used in oxide glass simulations. Each potential generates complete LAMMPS input configuration ready for simulation.

Unified Interface

All potentials are accessed through a single function:

generate_potential(atoms_dict, potential_type="pmmcs")

from amorphouspy import get_structure_dict, generate_potential

structure_dict = get_structure_dict({"SiO2": 75, "Na2O": 15, "CaO": 10}, target_atoms=3000)
potential = generate_potential(structure_dict, potential_type="pmmcs")

Parameters:

Parameter Type Default Description
atoms_dict dict — Structure dictionary from get_structure_dict()
potential_type str "pmmcs" One of "pmmcs", "bjp", "shik", "bmp-harmonic", "bmp-screened-harmonic", or "yang2026"

Returns: A pd.DataFrame with columns:

Column Description
Name Potential name identifier
Filename Associated table files (if any)
Model Model type descriptor
Species List of element species
Config List of LAMMPS input lines

The Config column contains a list of strings — each string is a LAMMPS input command that sets up the pair style, pair coefficients, charges, and any additional parameters needed for the simulation.

Comparison

Feature PMMCS BJP SHIK BMP-harm BMP-shrm Yang2026
Element coverage 28 elements 4 elements (CAS) 9 elements 36 elements 36 elements 5 elements (Na/Ca borosilicate)
Functional form Morse + \(r^{-12}\) Born-Mayer-Huggins Buckingham + \(r^{-24}\) Morse + Buck + harmonic 3b Morse + Buck + screened 3b Buckingham
Coulomb solver coul/dsf born/coul/dsf coul/dsf DSF / Wolf / PPPM / Ewald DSF / Wolf / PPPM / Ewald DSF (hybrid/overlay) / PPPM / Ewald
Cation charges Simple (multiples of 0.6) Simple (multiples of 0.6) Individually fitted Simple (multiples of 0.6) Simple (multiples of 0.6) Scaled (×0.5 from formal)
Oxygen charge Fixed (\(-1.2\)) Fixed (\(-1.2\)) Composition-dependent Fixed (\(-1.2\)) Fixed (\(-1.2\)) Fixed (\(-0.945\))
Three-body terms No No No Si/P triplets Si/P/B/V triplets No
Boron support Yes No Yes B-free only Yes (alkali/AE systems) Yes
Table files No No Yes (auto-generated) Yes (auto-generated) Yes (auto-generated) No
Best for General oxide glasses CAS systems Si/Al/B oxide glasses Multi-modifier silicates/phosphates Borates and borosilicates Na/Ca borosilicate glasses
Cutoff 8.0 Å 8.0 Å 10.0 Å 7.0 Å (SR), 8.0 Å (Coul) 7.0 Å (SR), 8.0 Å (Coul) 11.0 Å

Choosing a Potential

  • PMMCS — Use for general multi-component oxide glasses. Broadest element support (28 elements). Good default choice.
  • BJP — Use for calcium aluminosilicate (CAS) systems. Specifically parameterized for Ca-Al-Si-O.
  • SHIK — Use for silicate, aluminosilicate, and borosilicate glasses. Composition-dependent oxygen charge provides better accuracy for mixed-modifier systems.
  • BMP-harm — Use for multi-modifier silicate or phosphosilicate glasses without boron. Explicit harmonic three-body terms improve angular ordering around Si and P.
  • BMP-shrm — Use for borate and borosilicate glasses. The screened three-body form covers B and V triplets and is the recommended choice when boron is present.
  • Yang2026 — Use for Na/Ca borosilicate glasses (Na, Ca, B, Si, O). Transferable classical potential validated against machine-learning-optimized parameters.

Detailed Guides

Each potential has its own detailed page: