Activation Energy for the Decapsulation of Small Molecules from A-Type Zeolites

Potential energy function sets for some ion-exchanged A-type zeolites, K-A and Rb₁₁Na₁-A, were determined by introducing the X-ray crystal structures as constraints. The potential functions reproduced well the X-ray crystal structures of the monovalent ion-exchanged zeolites. The activation energies for the en- or decapsulation of small molecules (H₂, O₂, N₂, and CH₄) and inert gases from the α-cage of model zeolites (Na-A, K-A, Rb₁₁Na₁-A, and Cs₃Na₉-A) were obtained by the molecular mechanical calculations. The calculated activation energies agreed well with experimental results.