| Abstract
| - Molecular dynamics simulations at temperatures of 270, 330, and 390 K have been carried out to address thequestion of cation migration upon chloroform sorption in sodium zeolite Y. The results show that sodiumcations located in different sites exhibit different types of mobility. These may be summarized as follows: (1) SII cations migrate toward the center of the supercage upon sorption, due to interactions with the polarsorbate molecules. (2) SI‘ cations hop from the sodalite cage into the supercage to fill vacant SII sites. (3) SI‘cations migrate to other SI‘ sites within the same sodalite cage. (4) SI cations hop out of the double six-ringsinto SI‘ sites. In some instances, concerted motion of cations is observed. Furthermore, former SI‘ and SIcations, having crossed to SII sites, may then further migrate within the supercage, as in (1). The cationmotion is dependent on the level of sorbate loading, with 10 molecules per unit cell not being enough toinduce significant cation displacements, whereas the sorption of 40 molecules per unit cell results in a numberof cations being displaced from their original positions. Further rearrangement of the cation positions is observedupon evacuation of the simulation cell, with some cations reverting back to sites normally occupied in bareNaY.
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