Constrained Low-Dimensional Parametrization of Coarse-Grained Force Fields for Structural and Thermodynamic Consistency

For complex multicomponent condensed-phase systems, coarse-grained (CG) molecular dynamics often struggles to simultaneously achieve structural fidelity and thermodynamic consistency. Using base asphalt as a representative system, this study proposes and validates a hierarchical hybrid, closed-loop parametrization strategy. Bonded interactions are derived via iterative Boltzmann inversion (IBI) and further stabilized through robust statistical treatment and reduced representations, improving the parameter identifiability and numerical stability. Non-bonded interactions are built on the Martini 3 framework and are calibrated in a low-dimensional manner using only two global scaling factors, followed by geometric fine-tuning for the overall correction. The resulting model reproduces the density-temperature response within the experimentally relevant window and remains consistent with all-atom (AA) references in key structural statistics. Dynamically, it preserves the relative diffusion ranking among components and enables consistent time rescaling to the AA reference. Arrhenius-like diffusion behavior and the temperature dependence of the viscosity are also captured. At the mesoscale, the model reproduces the evolution of asphaltene self-aggregation, representative stacking-like local arrangements of aromatic-core regions, and bee-like morphological features consistent with experimental observations. Overall, this work provides a reproducible and parsimonious paradigm for CG force field construction in complex mixtures, enabling coupled convergence of structure and thermodynamics.