

fairchem
by the FAIR Chemistry team
fairchem
is the FAIR Chemistry's centralized repository of all its data, models,
demos, and application efforts for materials science and quantum chemistry.
:warning: FAIRChem version 2 is a breaking change from version 1 and is not compatible with our previous pretrained models and code.
If you want to use an older model or code from version 1 you will need to install version 1,
as detailed here.
:warning: Some of the docs and new features in FAIRChem version 2 are still being updated so you may see some changes over the next few weeks. Check back here for the latest instructions. Thank you for your patience!
Read our latest release post!
Read about the UMA model and OMol25 dataset release.

Try the demo!
If you want to explore model capabilities check out our
educational demo

Installation
Although not required, we highly recommend installing using a package manager and virtualenv such as uv, it is much faster and better at resolving dependencies than standalone pip.
Install fairchem-core using pip
pip install fairchem-core
If you want to contribute or make modifications to the code, clone the repo and install in edit mode
git clone git@github.com:facebookresearch/fairchem.git
pip install -e fairchem/packages/fairchem-core[dev]
Quick Start
The easiest way to use pretrained models is via the ASE FAIRChemCalculator
.
A single uma model can be used for a wide range of applications in chemistry and materials science by picking the
appropriate task name for domain specific prediction.
Instantiate a calculator from a pretrained model
Make sure you have a Hugging Face account, have already applied for model access to the
UMA model repository, and have logged in to Hugging Face using an access token.
You can use the following to save an auth token,
huggingface-cli login
Models are referenced by their name, below are the currently supported models:
uma-s-1p1 | Latest version of the UMA small model, fastest of the UMA models while still SOTA on most benchmarks (6.6M/150M active/total params) |
uma-m-1p1 | Best in class UMA model across all metrics, but slower and more memory intensive than uma-s (50M/1.4B active/total params) |
Set the task for your application and calculate
- oc20: use this for catalysis
- omat: use this for inorganic materials
- omol: use this for molecules
- odac: use this for MOFs
- omc: use this for molecular crystals
Relax an adsorbate on a catalytic surface,
from ase.build import fcc100, add_adsorbate, molecule
from ase.optimize import LBFGS
from fairchem.core import pretrained_mlip, FAIRChemCalculator
predictor = pretrained_mlip.get_predict_unit("uma-s-1p1", device="cuda")
calc = FAIRChemCalculator(predictor, task_name="oc20")
slab = fcc100("Cu", (3, 3, 3), vacuum=8, periodic=True)
adsorbate = molecule("CO")
add_adsorbate(slab, adsorbate, 2.0, "bridge")
slab.calc = calc
opt = LBFGS(slab)
opt.run(0.05, 100)
Relax an inorganic crystal,
from ase.build import bulk
from ase.optimize import FIRE
from ase.filters import FrechetCellFilter
from fairchem.core import pretrained_mlip, FAIRChemCalculator
predictor = pretrained_mlip.get_predict_unit("uma-s-1p1", device="cuda")
calc = FAIRChemCalculator(predictor, task_name="omat")
atoms = bulk("Fe")
atoms.calc = calc
opt = LBFGS(FrechetCellFilter(atoms))
opt.run(0.05, 100)
Run molecular MD,
from ase import units
from ase.io import Trajectory
from ase.md.langevin import Langevin
from ase.build import molecule
from fairchem.core import pretrained_mlip, FAIRChemCalculator
predictor = pretrained_mlip.get_predict_unit("uma-s-1p1", device="cuda")
calc = FAIRChemCalculator(predictor, task_name="omol")
atoms = molecule("H2O")
atoms.calc = calc
dyn = Langevin(
atoms,
timestep=0.1 * units.fs,
temperature_K=400,
friction=0.001 / units.fs,
)
trajectory = Trajectory("my_md.traj", "w", atoms)
dyn.attach(trajectory.write, interval=1)
dyn.run(steps=1000)
Calculate a spin gap,
from ase.build import molecule
from fairchem.core import pretrained_mlip, FAIRChemCalculator
predictor = pretrained_mlip.get_predict_unit("uma-s-1p1", device="cuda")
singlet = molecule("CH2_s1A1d")
singlet.info.update({"spin": 1, "charge": 0})
singlet.calc = FAIRChemCalculator(predictor, task_name="omol")
triplet = molecule("CH2_s3B1d")
triplet.info.update({"spin": 3, "charge": 0})
triplet.calc = FAIRChemCalculator(predictor, task_name="omol")
triplet.get_potential_energy() - singlet.get_potential_energy()
LICENSE
fairchem
is available under a MIT License. Models/checkpoint licenses vary by application area.
MIT License
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copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
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