where 𝑚 𝑖 and 𝐯 𝒊 are the mass and instantaneous velocity of the ith particle. The symbol ⊗ indicates the outer, dyadic, or direct tensor product. W is the global virial tensor, which depends only on the instantaneous atom positions 𝐫 𝑁 = 𝐫 1 , 𝐫 2 , … , 𝐫 N and the interactions between them. All the stress analysis was performed by a custom version of Gromacs, implementing an algorithm for virial stress calculation.