As a first step, FF-based MD simulations were used to evaluate whether TCS could diffuse through the pores of the six all-silica zeolites chosen for this study. For each zeolite, five trajectories were calculated, starting from the TCS@Zeo configurations that were also used as starting points for the DFT optimizations. ,550/573•10 -8 cm 2 s -1 computed for benzene/para-xylene in FAU at 300 K ). While diffusion is distinctly slower in IFR, it can be inferred that the TCS molecule is still able to move through the pores. No diffusion on the nanosecond timescale occurs for BEA, where TCS remains in the vicinity of its initial location during all 50 ns simulations. This finding disagrees with the experimental observation of a significant TCS uptake from aqueous solution in zeolite beta samples having different Si/Al ratios. Although the difference between the idealized all-silica BEA model used in the calculations and real zeolite beta samples, which exhibit stacking disorder of the tetragonal beta layers along the [001] direction, could be responsible for this discrepancy, other explanations cannot be ruled out. Altogether, the findings for BEA indicate that the MD simulations make a rather conservative estimate of the diffusion behavior, giving confidence in the prediction that TCS can diffuse through the pore systems of the other zeolites. Adsorption energies of TCS@Zeo complexes