Stability#
We’re going to start simple here - let’s run a local relaxation (optimize the unit cell and positions) using a pre-trained EquiformerV2-31M-OMAT24-MP-sAlex checkpoint. This checkpoint has a few fun properties
It’s a relatively small (31M) parameter model
It was pre-trained on the OMat24 dataset, and then fine-tuned on the MPtrj and Alexandria datasets, so it should emit energies and forces that are consistent with the MP GGA (PBE/PBE+U) level of theory
Need to install fairchem-core or get UMA access or getting permissions/401 errors?
Install the necessary packages using pip, uv etc
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from __future__ import annotations
import pprint
from ase.build import bulk
from ase.optimize import LBFGS
from quacc.recipes.mlp.core import relax_job
# Make an Atoms object of a bulk Cu structure
atoms = bulk("Cu")
# Run a structure relaxation
result = relax_job(
atoms,
method="fairchem",
name_or_path="uma-s-1p1",
task_name="omat",
opt_params={"fmax": 1e-3, "optimizer": LBFGS},
)
WARNING:root:device was not explicitly set, using device='cuda'.
WARNING:root:The 'seed' argument is deprecated and will be removed in future versions. Please set the seed in the MLIPPredictUnit configuration instead.
INFO:quacc.runners.prep:Calculation will run at /home/runner/work/fairchem/fairchem/docs/inorganic_materials/examples_tutorials/tmp-quacc-2025-08-26-17-41-28-605616-40240
INFO:quacc.runners.prep:Calculation results stored at /home/runner/work/fairchem/fairchem/docs/inorganic_materials/examples_tutorials/quacc-2025-08-26-17-41-28-605616-40240
pprint.pprint(result)
{'atoms': Atoms(symbols='Cu', pbc=True, cell=[[0.0, 1.805, 1.805], [1.805, 0.0, 1.805], [1.805, 1.805, 0.0]]),
'converged': np.True_,
'dir_name': '/home/runner/work/fairchem/fairchem/docs/inorganic_materials/examples_tutorials/quacc-2025-08-26-17-41-28-605616-40240',
'input_atoms': {'atoms': Atoms(symbols='Cu', pbc=True, cell=[[0.0, 1.805, 1.805], [1.805, 0.0, 1.805], [1.805, 1.805, 0.0]]),
'structure_metadata': {'builder_meta': {'build_date': datetime.datetime(2025, 8, 26, 17, 41, 29, 278976, tzinfo=datetime.timezone.utc),
'emmet_version': '0.84.9',
'pymatgen_version': '2025.6.14'},
'chemsys': 'Cu',
'composition': Composition('Cu1'),
'composition_reduced': Composition('Cu1'),
'density': 8.971719813140734,
'density_atomic': 11.761470249999999,
'elements': [Element Cu],
'formula_anonymous': 'A',
'formula_pretty': 'Cu',
'nelements': 1,
'nsites': 1,
'symmetry': {'angle_tolerance': 5.0,
'crystal_system': <CrystalSystem.cubic: 'Cubic'>,
'number': 225,
'point_group': 'm-3m',
'symbol': 'Fm-3m',
'symprec': 0.1,
'version': '2.6.0'},
'volume': 11.761470249999999}},
'name': 'fairchem Relax',
'nid': 'runnervmy6chb.04p4rmzsbequpadhmj22ussfqa.ex.internal.cloudapp.net',
'parameters': {'version': '2.4.0'},
'parameters_opt': {'fmax': 0.001,
'max_steps': 1000,
'maxstep': 0.2,
'optimizer': 'LBFGS',
'type': 'optimization'},
'quacc_version': '1.0.3',
'results': {'energy': -3.7501682869643735,
'forces': array([[0., 0., 0.]], dtype=float32),
'free_energy': -3.7501682869643735,
'stress': array([-4.3533556e-03, -4.3533775e-03, -4.3533528e-03, 1.0502985e-09,
3.2705114e-10, -1.2674874e-09], dtype=float32)},
'structure_metadata': {'builder_meta': {'build_date': datetime.datetime(2025, 8, 26, 17, 41, 29, 289914, tzinfo=datetime.timezone.utc),
'emmet_version': '0.84.9',
'pymatgen_version': '2025.6.14'},
'chemsys': 'Cu',
'composition': Composition('Cu1'),
'composition_reduced': Composition('Cu1'),
'density': 8.971719813140734,
'density_atomic': 11.761470249999999,
'elements': [Element Cu],
'formula_anonymous': 'A',
'formula_pretty': 'Cu',
'nelements': 1,
'nsites': 1,
'symmetry': {'angle_tolerance': 5.0,
'crystal_system': <CrystalSystem.cubic: 'Cubic'>,
'number': 225,
'point_group': 'm-3m',
'symbol': 'Fm-3m',
'symprec': 0.1,
'version': '2.6.0'},
'volume': 11.761470249999999},
'trajectory': [Atoms(symbols='Cu', pbc=True, cell=[[0.0, 1.805, 1.805], [1.805, 0.0, 1.805], [1.805, 1.805, 0.0]], calculator=SinglePointCalculator(...))],
'trajectory_results': [{'energy': -3.7501682869643735,
'forces': array([[0., 0., 0.]]),
'free_energy': -3.7501682869643735,
'stress': array([-4.35335562e-03, -4.35337750e-03, -4.35335282e-03, 1.05029851e-09,
3.27051136e-10, -1.26748745e-09])}]}
Congratulations; you ran your first relaxation using an OMat24-trained checkpoint and quacc!