Fig. 3.

Origin of the performance improvements in the ML-mW and ML-BOP models. a Solid line style curves compare the 2-body only interaction energy of ML-mW, mW, and ML-BOP (ϕ₃ = 0 for the mW models and b_ij = 1 for ML-BOP). The vertical dotted line marks the Tersoff cutoff switching distance (R−D) in ML-BOP. Dashed and dotted line style curves show the pair interaction energy of ML-mW and mW under the influence of a third atom, the addition of ϕ₃. b 3-body energy term, ϕ₃, evaluated at the minimum of the pair interaction energy curves, r_min. Note that we first identify r_min for each interatomic angle θ and then compute the corresponding ϕ_3. The cross marks indicate the θ at which the interaction energy curves in (a) are evaluated. c The explicit cutoff function, f_c, in Tersoff provides a flexibility to independently modify the tail portion of the pair interaction energy curve (inset). This influences the relative separation between melting point (cross marks) and TMD (vertical dotted lines) in the temperature-dependent density plot