arXiv:2511.01913physics.chem-phcond-mat.mtrl-sci2025-11被引 2

提出Δ-sGDML模型,精准分离共价与非共价作用力,提升分子力场精度。

Delta-learned force fields for nonbonded interactions: Addressing the strength mismatch between covalent-nonbonded interaction for global models

  • 分片段训练加结合模型,显式解耦分子内与分子间物理机制
  • 在苯二聚体等系统中力误差降低最高达75%,能量精度不下降
  • 适合需要高精度非共价相互作用的分子模拟研究者使用

非共价相互作用(如范德华色散、氢键、离子-π作用、π-堆积)主导材料与分子体系的结构、动力学及涌现现象,但将其与共价力一并准确学习仍是机器学习力场(MLFF)的核心挑战。针对全局模型在多片段设置下使用库仑矩阵(CM)描述符时,因欧氏/弗罗贝尼乌斯度量导致的分子内特征过度表征问题,本文揭示了共价力标签与CM对分子间特征的过强表达之间存在强度失配,造成单模型训练偏差和力场保真度下降。为此,提出Δ-sGDML:在sGDML框架内引入尺度感知设计,通过分片段模型与专用结合模型联合训练,推理时组合生成力场。在苯二聚体、主客体复合物(C₆₀@buckycatcher、NO₃⁻@i-corona[6]arene)、苯-水及苯-Na⁺体系中,Δ-sGDML一致优于单一全局模型,片段级力误差最高降低75%,且能量精度无损失。分子动力学模拟进一步验证,Δ模型在10–400 K范围内对C₆₀@buckycatcher产生稳定轨迹,而单全局模型在约200 K以上即失稳。该方法为统一各片段误差、恢复全局MLFF中的可靠非共价物理提供了实用路径。

原文摘要 · Abstract (English)

Noncovalent interactions--vdW dispersion, hydrogen/halogen bonding, ion-$π$, and $π$-stacking--govern structure, dynamics, and emergent phenomena in materials and molecular systems, yet accurately learning them alongside covalent forces remains a core challenge for machine-learned force fields (MLFFs). This challenge is acute for global models that use Coulomb-matrix (CM) descriptors compared under Euclidean/Frobenius metrics in multifragment settings. We show that the mismatch between predominantly covalent force labels and the CM's overrepresentation of intermolecular features biases single-model training and degrades force-field fidelity. To address this, we introduce \textit{$Δ$-sGDML}, a scale-aware formulation within the sGDML framework that explicitly decouples intra- and intermolecular physics by training fragment-specific models alongside a dedicated binding model, then composing them at inference. Across benzene dimers, host-guest complexes (C$_{60}$@buckycatcher, NO$_3^-$@i-corona[6]arene), benzene-water, and benzene-Na$^+$, \mbox{$Δ$-sGDML} delivers consistent gains over a single global model, with fragment-resolved force-error reductions up to \textbf{75\%}, without loss of energy accuracy. Furthermore, molecular-dynamics simulations further confirm that the $Δ$-model yields a reliable force field for C$_{60}$@buckycatcher, producing stable trajectories across a wide range of temperatures (10-400~K), unlike the single global model, which loses stability above $\sim$200~K. The method offers a practical route to homogenize per-fragment errors and recover reliable noncovalent physics in global MLFFs.

力场学习非共价作用分子模拟

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