Comparing Empirical and Physics-Based Models of Intermolecular Dispersion and Repulsion Energies

= 0.956, with SAPT data. A distance-dependent analysis showed that correlation improves with increasing dimer separation (0.80 to 1.1 factor from equilibrium distance). Together, these results demonstrate that the empirical model, supported by optimized parameters, offers a computationally efficient and accurate alternative to high-level quantum mechanical methods. The physical model further emphasizes the significance of accurate electron density and polarizability parameters for correct vdW interaction estimation, without the need for ad-hoc fitted atomic parameters. Validation against a separate benchmark of protein side chain-side chain interactions (SSI) confirmed that both models effectively capture key noncovalent interactions in biologically important molecular systems.