Eover for heavy atoms In Lammps code, the calculation for the cases with atom mass > 21 g/mol has slightly different results from formulation given in ref [1]. 𝐸 𝑜𝑣𝑒𝑟 = 𝑝 𝑜𝑣1 𝐷 𝑒 𝜎 𝐵𝑂 𝑖𝑗 ∆ 𝑖 𝑙𝑝𝑐𝑜𝑟𝑟 + 𝑉𝑎𝑙 𝑖 ∆ 𝑖 𝑙𝑝𝑐𝑜𝑟𝑟 1 1+exp⁡ 𝑝 𝑜𝑣2 ∆ 𝑖 𝑙𝑝𝑐𝑜𝑟𝑟 ∆ 𝑖 𝑙𝑝𝑐𝑜𝑟𝑟 = ∆ 𝑖 − ∆ 𝑖 𝑙𝑝 1+ 𝑝 𝑜𝑣3 𝑒𝑥𝑝 𝑝 𝑜𝑣4 ∆ 𝑗 − ∆ 𝑗 𝑙𝑝 𝐵𝑂 𝑖𝑗 𝜋 + 𝐵𝑂 𝑖𝑗 𝜋𝜋 This term becomes 0 for atom mass > 21 g/mol. I think this should be for atoms > 210 g/mol. lib/reax/reax_poten.F line 1119 1. Mueller, J. E., et al . J. Phys. Chem. C. 4939–4949 (2010). - Formulation is from its supporting material.

W/ 21.0 g/mol exception, the shape of EOS can not be followed. if (amas(ity1).gt.21.0) if (amas(ity1).gt.210.0) W/ 21.0 g/mol exception, the shape of EOS can not be followed. The ignored term need to be included as you can see in the graph below.