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
This code will download the appropriate checkpoint from huggingface_hub automatically; if you don’t have the right access token specified, you’ll hit an permission or 401 error.
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-1",
task_name="omat",
opt_params={"fmax": 1e-3, "optimizer": LBFGS},
)
/home/runner/work/_tool/Python/3.12.11/x64/lib/python3.12/site-packages/torchtnt/utils/version.py:12: UserWarning: pkg_resources is deprecated as an API. See https://setuptools.pypa.io/en/latest/pkg_resources.html. The pkg_resources package is slated for removal as early as 2025-11-30. Refrain from using this package or pin to Setuptools<81.
import pkg_resources
WARNING:root:device was not explicitly set, using device='cuda'.
INFO:root:Setting random seed to 41
INFO:root:Setting random seed to 41
INFO:quacc.runners.prep:Calculation will run at /home/runner/work/fairchem/fairchem/docs/inorganic_materials/examples_tutorials/tmp-quacc-2025-06-18-15-10-45-724451-59941
INFO:quacc.runners.prep:Calculation results stored at /home/runner/work/fairchem/fairchem/docs/inorganic_materials/examples_tutorials/quacc-2025-06-18-15-10-45-724451-59941
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-2025-06-18-15-10-45-724451-59941',
'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, 6, 18, 15, 10, 46, 438827, tzinfo=datetime.timezone.utc),
'emmet_version': '0.84.8',
'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': 'runnervm1w6u6.qbgdzmcscruuffo0kelb5mxrja.dx.internal.cloudapp.net',
'parameters': {'version': '2.2.1.dev23+g5a2c0baa'},
'parameters_opt': {'fmax': 0.001,
'max_steps': 1000,
'maxstep': 0.2,
'optimizer': 'LBFGS',
'type': 'optimization'},
'quacc_version': '0.16.0',
'results': {'energy': -3.7579006783217954,
'forces': array([[0., 0., 0.]], dtype=float32),
'free_energy': -3.7579006783217954,
'stress': array([-6.3946932e-03, -6.3946899e-03, -6.3946894e-03, 2.6963240e-10,
-2.7428915e-09, -2.5426519e-09], dtype=float32)},
'structure_metadata': {'builder_meta': {'build_date': datetime.datetime(2025, 6, 18, 15, 10, 46, 449686, tzinfo=datetime.timezone.utc),
'emmet_version': '0.84.8',
'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': -3.7579006783217954,
'forces': array([[0., 0., 0.]]),
'free_energy': -3.7579006783217954,
'stress': array([-6.39469316e-03, -6.39468990e-03, -6.39468944e-03, 2.69632400e-10,
-2.74289147e-09, -2.54265187e-09])}]}
Congratulations; you ran your first relaxation using an OMat24-trained checkpoint and quacc!