STRUCTURE OF HELIUM AND NEON IN ZEOLITE

We have measured the structure of helium and neon adsorbed in zeolite 13X at temperatures in the range 5.5-80 K. No evidence for bulklike Li quid or solid behavior is observed for the temperatures studied. Inste ad, both the He and Ne atoms adsorb into well-defined sites in the zeo lite structure. The sites occupied appear to be the same for He and Ne and are consistent with the adsorption sites previously identified fo r D-2 in 13X. We have also measured the dependence of the structure on pore filling for helium over a limited range of filling.