A LoRA fine-tunedMACE (Multi-Atomic
Cluster Expansion) foundation model for ionic lithium–fluoride systems. This
model is built on the MACE-MP-0 OMAT medium checkpoint and fine-tuned on
Quantum ESPRESSO DFT data covering bulk LiF, LiF interfaces, isolated
frames.
This model is directly produced by the mlpdft project.
Model Details
Model Description
MACE (Multi-Atomic Cluster Expansion) is an equivariant message-passing neural
network that constructs many-body expansions with learnable radial and angular
features. It achieves state-of-the-art accuracy while maintaining speed
suitable for molecular dynamics simulations of thousands of atoms.
This variant is fine-tuned via LoRA (Low-Rank Adaptation) on the
MACE-MP-0 OMAT-medium foundation model to improve transfer to ionic
lithium–fluoride chemistries.
Developed by: Jorge Munoz (mlpdft project)
Base model: MACE-MP-0 OMAT medium (mace_omat_medium)
Model type: Equivariant message-passing neural network (E(3)-equivariant)
The model was fine-tuned on the
jorgemunozl/minimal_li_f_mace_dataset
dataset, which contains DFT calculations (Quantum ESPRESSO, PBEsol,
PAW pseudopotentials) spanning 8 groups:
Group
Description
LIF64_KJPAW_V2
Bulk LiF — NVE / NPT trajectories
LIF64_ISOLATED
Isolated bulk LiF frames
LIFINTERFACE_KJPAW_V1
LiF interface (first version)
LIFINTERFACE_KJPAW_NPT
LiF interface — NPT
LIFINTERFACE_KJPAW_NPT_V2
LiF interface — NPT (second version)
LIWITHF_V3
Li + F slabs
LIWITHF_ISOLATED
Isolated Li + F frames
LIWITHF_NPT_FINAL
Li + F — NPT (final)
Each frame carries:
REF_energy — total DFT energy (eV)
REF_forces — per-atom forces (eV/Å)
stress — stress tensor (when available)
Energy offsets (isolated-atom energies in eV):
Element
Atomic number
Isolated atom energy
Li
3
-15.11995 × RY_TO_EV
F
9
-58.46236 × RY_TO_EV
RY_TO_EV ≈ 13.605698
Training Procedure
Fine-tuning hyperparameters
Hyperparameter
Value
Architecture
MACE
Cutoff radius (r_max)
5.0 Å
Message-passing channels
128
Max spherical harmonics (max_L)
1 (scalars + vectors)
Max ell order (max_ell)
3
Interaction blocks
2
Body order (correlation)
3 (4-body)
Radial basis functions
8
Cutoff basis functions
5
Optimization
Optimizer
Adam (AMSGrad)
Learning rate
0.01
Weight decay
5 × 10⁻⁷
Gradient clipping
10.0
Scheduler
ReduceLROnPlateau
LR decay factor
0.8
Scheduler patience
50 epochs
Max epochs
10
Batch size
8
Early stopping patience
4
Validation fraction
50%
Loss
Weighted
Energy weight
1.0
Forces weight
1.0
LoRA fine-tuning
LoRA enabled
Yes
LoRA rank
8
Regularization
SWA (stochastic weight averaging)
Disabled
EMA (exponential moving average)
Yes (decay 0.99)
Precision
float64
Training script
Fine-tuning is done via the mace_run_train CLI from the mace-torch
package, driven by src/mlpdft/train.py. See the
mlpdft README for full details.
uv run python src/mlpdft/train.py
Hardware
Training was performed on CUDA GPU RTX4000ADA support (device="cuda").
Evaluation
Metrics
Evaluation metrics are computed per group on energy and forces:
Metric
Description
MAE
Mean Absolute Error
RMSE
Root Mean Square Error
MaxAE
Maximum Absolute Error
MAE per atom
Energy MAE divided by number of atoms
Evaluation is run via:
uv run python src/mlpdft/evaluate_mace_metrics.py
The script runs the model on all groups from the dataset and prints
a summary table with energy and force errors.
Technical Specifications
Model Architecture and Objective
MACE is a body-ordered equivariant message-passing neural network:
Input: Atomic numbers and Cartesian positions
Embeddings: One-hot atomic number → learnable scalar features
Message passing: Atomic cluster expansion (ACE) basis with radial
Bessel basis + spherical harmonics for angular information
Readout: Site energies summed to total energy; forces via
automatic differentiation
Output: Total energy (eV) and per-atom forces (eV/Å)
Compute Infrastructure
Framework: PyTorch 2.x + mace-torch ≥ 0.3.6
Hardware requirements: CPU for inference; GPU recommended for large-scale MD
Citation
If you use this model, please cite both the MACE foundation model and the
CHGNet paper:
bibtex
1@article{batatia2023foundation,
2 title={A foundation model for atomistic materials chemistry},
3 author={Ilyes Batatia and Philipp Benner and Yuan Chiang and Alin M. Elena
4 and Fabian Zills and Gábor Csányi},
5 year={2023},
6 eprint={2401.00096},
7 archivePrefix={arXiv},
8 primaryClass={physics.chem-ph}
9}
bibtex
1@article{deng2023chgnet,
2 title={CHGNet: Pretrained universal neural network potential
3 for charge-informed atomistic modeling},
4 author={Bowen Deng and Peichen Zhong and KyuJung Jun
5 and Janosh Riebesell and Kevin Han and Christopher J. Bartel
6 and Gerbrand Ceder},
7 year={2023},
8 eprint={2302.14231},
9 archivePrefix={arXiv},
10 primaryClass={cond-mat.mtrl-sci}
11}