For the six all-silica zeolites, Boltzmann-weighted adsorption energies ∆𝐸 , as well as adsorption and deformation energies of the lowest-energy TCS@Zeo configurations are compiled in Table (results for all configurations are given in Table ). With the exception of FAU, the adsorption energies of the other five all-silica zeolites fall in a relatively narrow range from -153 to -160 kJ mol -1 . While the weaker interaction in FAU can be explained with the much larger pore diameter, resulting in reduced dispersion interactions between TCS and the pore walls, there is no apparent correlation of the adsorption energy with pore diameter and/or framework density for the remaining systems. The deformation energies are always small, with the sum of the two ∆𝐸 terms amounting to less than 5% of the total adsorption energy in all zeolites except MOR (where it reaches 6.5%). Rather different observations were made in the earlier DFT study of CBZ adsorption, where the sum of the deformation energies exceeded 10% of the total adsorption energies for some zeolites, notably BEA and MOR. Whereas the CBZ molecule is rather rigid, containing a tricyclic aromatic system, TCS can adjust much more easily to different pore environments because the two phenyl rings can rotate essentially independently. The flexibility manifests in the variation of the angle 𝜔 , which amounts to 89.0° in the crystal structure of triclosan at 150 K. This angle is reduced to 75.9° in the DFT-optimized structure of isolated TCS, and 𝜔 values varying from 53.9 to 92.5° occur in the lowest-energy TCS@Zeo complexes. There is no apparent correlation with the magnitude of the ∆𝐸 , term (Table ).