Journal article ยท Preprint article
Mode damping in a commensurate monolayer solid
The normal modes of a commensurate monolayer solid may be damped by mixing with elastic waves of the substrate. This was shown by Hall, Mills, and Black [Phys. Rev. B 32, 4932 (1985)], for perpendicular adsorbate vibrations in the presence of an isotropic elastic medium. That work is generalized with an elastic-continuum theory of the response of modes of either parallel or perpendicular polarization for a spherical adsorbate on a hexagonal substrate.
The results are applied to the discussion of computer simulations and inelastic atomic-scattering experiments for adsorbates on graphite. The extreme anisotropy of the elastic behavior of the graphite leads to quite different wave-vector dependence of the damping for modes polarized perpendicular and parallel to the substrate.
A phenomenological extension of the elasticity theory of the graphite to include bond-bending energies improves the description of substrate modes with strong anomalous dispersion, and enables a semiquantitative account of observed avoided crossings of the adlayer perpendicular vibration mode and the substrate Rayleigh mode.
Language: | English |
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Year: | 1997 |
Pages: | 1782-1792 |
ISSN: | 1550235x , 24699950 , 10953795 and 01631829 |
Types: | Journal article and Preprint article |
DOI: | 10.1103/PhysRevB.55.1782 |
0001 SURFACE CORRUGATION FILMS GRAPHITE HELIUM-ATOM SCATTERING KRYPTON LATTICE-DYNAMICS MOLECULAR-DYNAMICS PHONON-DISPERSION SINGLE-CRYSTAL SURFACE