Eads [kJ mol ] To begin with, it is useful to compare the adsorption energy of 5-FU@FAU_fwAloct_2Al to values computed for other FAU models in a previous computational study using a largely analogous setup: In that work, an Eads value of -73 kJ mol -1 was obtained for an all-silica FAU model, whereas the adsorption energy for 5-FU interacting with a single framework proton (H-FAU_1H) amounted to -144 kJ mol -1 (a re-calculation in the context of the present work that used TZVP, rather than DZVP, basis sets for the entire optimisation resulted in a marginally changed value of -146 kJ mol -1 ). Thus, the interaction of 5-FU with a Lewis acidic Aloct site is considerably stronger than for an all-silica zeolite, but significantly weaker than the interaction with a Brønsted acidic site in a protonic zeolite. The negative replacement energies on the order of - Incidentally, the contributions of the different interaction types result in a near-identical total interaction strength, and it can hence be assumed that both bonding scenarios can co-exist in real systems.