6.

Ca–O_w RDFs computed from the four models at three representative Ca–C distances: (a) Bidentate CIP minimum (R _Ca–C = 2.8 Å)), (b) monodentate CIP minimum (R _Ca–C = 3.3 Å) and (c) SSHIP minimum (R _Ca–C = 4.8 Å). The fine-tuned emb-DFT-SCAN model agrees nearly perfectly with the full DFT-SCAN model, which is remarkable, given that no forces (only energies) from emb-DFT-SCAN were used in the fine-tuning. The first solvation shell structure ( $R_{\mathrm{Ca}-{\mathrm{O}}_{\mathrm{W}}}\approx 2.4$ Å) predicted by both fine-tuned models differs qualitatively from the baseline DFT-revPBE-D3­(BJ) model.