Crystal structures of the zeolites considered were extracted from the literature (references in Table ). If present, partial occupancies of T sites by elements other than Si were ignored, resulting in all-silica zeolites models. In some cases, the published crystal structures show signs of local disorder, such as linear or near-linear Si-O-Si linkages that arise from a (static or dynamic) disorder of the oxygen atoms. While these linkages will, in many cases, not undergo pronounced changes when optimizing the guest-free structure, the inclusion of the guest molecule could cause a relaxation towards a lower-energy local structure. This would cause an artificial favourable contribution to the adsorption energy that is, in fact, purely due to framework relaxation (in such cases, the deformation energy ∆ , would become negative). To avoid such artefacts, DFT-based MD simulations were first run for the guest-free zeolite structures, fixing the unit cell parameters to experimental values and using appropriately sized supercells where required. For each zeolite, the average structure over the production part of the AIMD trajectory was then extracted, and a symmetry search was performed. In many cases, this resulted in structures having lower symmetry than the experimental structures (Table ). These average structures were then again DFT-optimized.