Effective Volume Correction for Lennard-Jones Static Potential Matching on Coarse-Graining Small Molecules

Coarse-grained (CG) models have been widely employed in simulating the functionality of complex systems due to their lower computational demand, and the accuracy of their simulation outcomes critically depends on their parameters. In the previous study, we developed a general CG potential matching method called the Lennard-Jones Static Potential Matching (LJSPM) method for Lennard-Jones (LJ) interactions, which enables users to derive inter-system transferable LJ parameters efficiently by using only one arbitrary molecular structure. The LJSPM offers a significant means for developing physical-based non-bonded interaction parameters in CG models. However, previous results show that LJSPM generally underestimates LJ repulsive contributions, which leads to mismatching of the CG and AA LJ potential energy surfaces for short-ranged non-bonded pairs. In this work, a physical-based, general, and efficient method named the effective volume correction (EVC) is proposed to fulfill the underestimated short-ranged LJ exclusion effects for CG-LJ parameters matched by the LJSPM method. This new EVC-based LJSPM method can accurately reproduce density, the rational distribution function, and the solvation free energy of small organic molecules including alkanes, alcohols, and amines. This indicates that the EVC-based LJSPM method exhibits good transferability for the development of CG models in small molecules.