To further test our model, we also built and studied crystal arrays of PET polymer chains in vacuum and in water (Figure ). In crystalline PET, the repetitive linear pattern of the polymer chains (Figure ) forces a Ψ t of approximately 180 • in all PET monomers, yielding nearly 100% trans content. This same pattern was observed in our simulations in vacuum and in water, with average |Ψ t | values of 172 ± 7 • and 172 ± 9 • , respectively (Figure ).