X-ray and heat-capacity study of molecular oxygen adsorbed on graphite

In a comprehensive x-ray scattering and heat-capacity study of O2 physisorbed onto basal planes of graphite, at least four independent solid phases are found, whose characters differ markedly from previous descriptions. The most important change is for the monolayer phase, which is believed to consist of a rectangular lattice with the molecules lying down on the graphite surface. The precise nature of several of the higher coverage phases remains unknown. © 1980 The American Physical Society.