SORPTION OF XENON IN ZEOLITE-RHO - A THERMODYNAMIC SIMULATION STUDY

Molecular dynamics simulations of the sorption of xenon at 360 K in ze olite rho are reported. The xenon-solid potential is taken to be a pai rwise sum of xenon-oxide interactions, with parameters adjusted to giv e agreement with the experimental Henry's law constants. Energies of a dsorption and the distributions of sorbed atoms in the cage/window sys tem were evaluated as a function of the xenon loading in the zeolite. It is shown that increasing loading produces an increase in the (negat ive) xenon-xenon average energy which is compensated by a decrease in the (negative) xenon-solid energy. The atomic distributions show that the xenon atoms are initially tightly sorbed in the cage windows. Once these are filled, additional xenons show chaotic, fluidlike trajector ies in the cages. However, at the highest xenon loadings, even the ato ms in the cages become localized into an ordered structure.