The fit of the CBZ molecule into the zeolite pores can be assessed in a qualitative way by visualizing the lowest-energy configuration of adsorbed CBZ together with a contour of the DFT-computed electron density, which represents (approximately) the outline of the accessible part of the zeolite pores. Figure shows the results for the lowest-energy configurations of CBZ in three zeolites with one-dimensional 12MR channels, IFR, AFI, and ATS. For IFR, it is clearly visible that CBZ fits very well into the pores, with the bent CBZ molecule being commensurate with a segment of the zig-zag channels of IFR (the angle between planes defined by the phenyl rings is only slightly increased with respect to the free molecule). In the case of AFI, where the channels are essentially cylindrical with a slightly undulating outline, the dibenzazepine system of CBZ appears to align with one side of the pore wall. The carboxamide group is oriented towards the other side, with the -NH2 group pointing into one of the "bulges" of the channels. The last system visualized in Figure , ATS, possesses elliptical channels. Although the CBZ ring system is significantly distorted in order to fit into the pores of this zeolite, as already discussed above, the projection along the channel axis in particular shows that even the flattened CBZ molecule cannot orient in a way that would result in a favourable alignment with the pore wall. A similar issue arises for the fourth zeolite with 1D 12MR channels, MOR (Figure ). A tendency to favour adsorption in zeolites with cylindrical channels over those with elliptical channels can also be observed among the three zeolites with 1D 14MR pore systems: Here, the interaction is strongest for CFI, which has essentially cylindrical channels, and distinctly weaker for DON and SFH, whose channels are elliptically distorted. In these cases, the distortion of the adsorbed CBZ molecule does not play a major role, with all values of ∆ , being small.