Monolayer Kr films adsorbed on BN

We have conducted a detailed study of Kr films adsorbed on BN. We have performed adsorption-isotherm measurements and calculations for the potential energy of Kr atoms on the surface of BN. Both the experimental and the theoretical results are extensively compared to data for Kr on graphite, as well as to data for ${\mathrm{N}}_2$ and CO on both BN and graphite. For ${\mathrm{N}}_2$ and CO, the energy calculations found similar corrugations on BN and on graphite (these two molecular adsorbates do not discriminate between the B and N atoms on the BN substrate). This is not the case for Kr. The corrugation for Kr atoms (which do discriminate between B and N) is quite different on BN from what it is on graphite. Our adsorption isotherms indicate that a commensurate solid phase is present for Kr on BN. However, this commensurate solid exists only over a surprisingly narrow temperature interval of less than 5 K. Our experimental results are compared with those from previous studies of this system. We offer possible explanations for the differences observed and attempt to present a coherent picture of the experimental situation for this system. © 1996 The American Physical Society.