Xe adsorption on a C60 monolayer on Ag(111)

S. M. Gatica, H. I. Li, R. A. Trasca, Milton Walter Cole, R. D. Diehl

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Abstract

Low-energy electron diffraction (LEED) experiments and grand canonical Monte Carlo simulations were carried out to study the adsorption of Xe on a substrate composed of a monolayer of C60 molecules on a Ag(111) surface. LEED adsorption isobars indicated that the adsorption occurs in steps, with the Xe initially adopting a structure having the same unit cell as the C60. Isosteric heats corresponding to the first two steps were measured to be 234±8 and 204±14 meV, respectively. For the simulations, the interaction potential of Xe with the composite substrate was modeled as the sum of two parts: the Xe-Ag part was computed using an ab initio van der Waals potential that varies as an inverse-distance cubed and the Xe- C60 part was computed using a spherically averaged C60 potential. The resulting adsorption potential is highly corrugated, with the most attractive sites located in the threefold hollows between the C60 molecules, forming a honeycomb array. The simulations (at temperatures ranging from 55 to 90 K) show that these attractive sites are filled first, followed by adsorption in two types of secondary sites, where a competition exists due to steric hindrance. The thermodynamic properties of film growth obtained in the simulation are in good agreement with the experiment.

Original languageEnglish (US)
Article number045414
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume77
Issue number4
DOIs
StatePublished - Jan 18 2008

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All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Gatica, S. M., Li, H. I., Trasca, R. A., Cole, M. W., & Diehl, R. D. (2008). Xe adsorption on a C60 monolayer on Ag(111). Physical Review B - Condensed Matter and Materials Physics, 77(4), [045414]. https://doi.org/10.1103/PhysRevB.77.045414