Abstract
Rare gases such as He, Ne and Ar are trapped in the lattice of solid C60 and (NaH)4C60 under conditions of ambient temperature and pressure. The mass analyzed thermal desorption reveals that rare gases are desorbed above 400K and their desorption amounts are in nonstoichiometric level. Ar2p and Ar3s X-ray photoelectron spectra show large chemical shifts. These results suggest that He, Ne and Ar have charge and are in valence state.