Inter-adsorbate forces and coherent scattering in helium spin-echo experiments

David J. Ward*, Arjun Raghavan, Anton Tamtögl, Andrew P. Jardine, Emanuel Bahn, John Ellis, Salvador Miret-Artès, William Allison

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


In studies of dynamical systems, helium atoms scatter coherently from an ensemble of adsorbates as they diffuse on the surface. The results give information on the co-operative behaviour of interacting adsorbates and thus include the effects of both adsorbate–substrate and adsorbate–adsorbate interactions. Here, we discuss a method to disentangle the effects of interactions between adsorbates from those with the substrate. The result gives an approximation to observations that would be obtained if the scattering was incoherent. Information from the experiment can therefore be used to distinguish more clearly between long-range inter-adsorbate forces and the short range effects arising from the local lattice potential and associated thermal excitations. The method is discussed in the context of a system with strong inter-adsorbate interactions, sodium atoms diffusing on a copper (111) surface.
Original languageEnglish
Pages (from-to)7799-7805
Number of pages7
JournalPhysical Chemistry, Chemical Physics
Issue number13
Early online date7 Oct 2020
Publication statusPublished - 7 Apr 2021


  • Diffusion
  • Surface analysis

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Fields of Expertise

  • Advanced Materials Science

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