X-ray Diffraction Study of the Structure of Xenon Multilayers on Single Crystal Graphite.

摘要

The structures of xenon multilayers (1 to 44 layers) physisorbed onto a graphite single crystal surface have been studied using x-ray scattering techniques. Both the intra-planar and inter-planar structures could be examined by measurements of the (1 0 l) diffraction rods. The (0 0 l) diffraction provides direct information about the thickness of the multilayer. We find two principal and surprising results. First, the xenon does not form an infinite number of layers at low temperatures. This disagrees with a number of previous reports which suggest complete wetting of xenon on graphite. Second, the structures of the adsorbed layers turn out to be rather elaborate. Instead of uniform, defect free layers, the xenon multilayers exhibit stacking disorder and a commensurate-incommensurate transition in the first layer. Keywords: Reprints; Wetting phenomena. (KT)