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On the Prospect of Chemically Transferable Coarse-Grained Electronic Models for Soft Materials
Katherine M Kidder1, Seonghwan Kim2, Nicholas E Jackson1,3
1Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.
The Journal of Physical Chemistry. B
|May 12, 2026
Summary
Chemically transferable electronic coarse-graining (ECG) models predict electronic properties from coarse-grained (CG) structures. Improving CG representations enhances chemical generalization but requires force fields that preserve quantum chemistry-compatible local structures.
Area of Science:
- Computational chemistry
- Materials science
- Polymer science
Background:
- Electronic coarse-graining (ECG) enables prediction of quantum-mechanical electronic properties from coarse-grained (CG) molecular configurations.
- This approach facilitates electronic property predictions at mesoscopic length scales, bridging the gap between atomistic and continuum methods.
- Assessing the chemical transferability of ECG models is crucial for their application to diverse chemical systems, particularly polymers.
Purpose of the Study:
- To diagnostically assess the feasibility of chemically transferable ECG models for predicting Highest Occupied Molecular Orbital (HOMO) energy.
- To evaluate ECG model performance across various chemical representations, including all-atom, united-atom, and Martini-scale.
- To investigate the impact of representation degeneracy challenges at the Martini scale and propose solutions.
Main Methods:
- Developed and applied an Element-Count-Label (ECL) representation to augment standard Martini beads with stoichiometric data.
- Compared ECG model performance using different levels of coarse-graining (all-atom, united-atom, Martini-scale).
- Analyzed the configurational distribution sampled by CG force fields against the distribution underlying DFT-parametrized ECG models.
Main Results:
- The proposed ECL representation significantly improved chemical generalization across diverse polymer chemistries by reducing mapping degeneracy.
- Despite improved chemical resolution, ECG models failed to recover electronic property distributions absent from the CG force field's sampled configurational space.
- A discrepancy was observed between the local molecular structure sampled by the CG force field and that used to parameterize the ECG model.
Conclusions:
- Chemically transferable ECG models require CG force fields that explicitly preserve quantum chemistry-compatible local molecular structure.
- Future Martini-like force fields must balance macroscopic thermodynamic and structural fidelity with the preservation of local electronic structure information.
- Addressing representation degeneracy and ensuring accurate sampling of local molecular configurations are key challenges for advancing ECG methods.
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