Before running the NVT simulations, each of the six supercells mentioned earlier was equilibrated for 1 ns using MonteCarloAnisotropicBarostat set to 1 atm at the relevant temperature. Although Open MM does not provide estimates of instantaneous pressure, the average box shapes equilibrated qualitatively well, according to the histograms of the box lengths during the simulation. Out of the 10,000 structures sampled during these simulations, a single structure with a box most similar to the average box was selected as the initial structure for all subsequent NVT simulations.