Angular distributions and surface-phonon dispersion curves have been measured by He-atom scattering for clean Pt between T=160 and 373 K and for Pt-H(1×1) at 160 K along the 〈110〉 and 〈112〉 azimuths. Inelastic-scattering intensities over a wide range of wave vectors are also reported for the clean surface. The results are analyzed with use of the distorted-wave Born approximation for a model potential describing the He-atom–Pt-surface potential. A set of 14 force constants adjusted to the bulk-phonon dispersion data cannot explain the measured time-of-flight spectra and the observed first-layer relaxation. However, by modifying at the surface the nearest-neighbor tangential force constants (α1’’=1.7α1b, and α1’=1.3α1b), the radial force constants (β1’’=0.39β1b), and the three-body force constant (γ1’’=0.037γ1b)— where the superscripts ∥ and ⊥ denote forces within the surface plane and between the first and second planes, respectively—a good fit to all the data is achieved. The new surface force constants are discussed in terms of electronic-charge redistribution within the first layer.

Surface phonons on the Pt(111) surface: a comparison of He-scattering experiments with lattice dynamical calculations / BORTOLANI, Virginio; FRANCHINI, Anna; SANTORO, Giorgio; TOENNIES, J. P.; WOLL, C. H.; ZHANG, G.. - In: PHYSICAL REVIEW. B, CONDENSED MATTER. - ISSN 0163-1829. - STAMPA. - 40:(1989), pp. 3524-3545. [10.1103/PhysRevB.40.3524]

Surface phonons on the Pt(111) surface: a comparison of He-scattering experiments with lattice dynamical calculations

BORTOLANI, Virginio;FRANCHINI, Anna;SANTORO, Giorgio;
1989

Abstract

Angular distributions and surface-phonon dispersion curves have been measured by He-atom scattering for clean Pt between T=160 and 373 K and for Pt-H(1×1) at 160 K along the 〈110〉 and 〈112〉 azimuths. Inelastic-scattering intensities over a wide range of wave vectors are also reported for the clean surface. The results are analyzed with use of the distorted-wave Born approximation for a model potential describing the He-atom–Pt-surface potential. A set of 14 force constants adjusted to the bulk-phonon dispersion data cannot explain the measured time-of-flight spectra and the observed first-layer relaxation. However, by modifying at the surface the nearest-neighbor tangential force constants (α1’’=1.7α1b, and α1’=1.3α1b), the radial force constants (β1’’=0.39β1b), and the three-body force constant (γ1’’=0.037γ1b)— where the superscripts ∥ and ⊥ denote forces within the surface plane and between the first and second planes, respectively—a good fit to all the data is achieved. The new surface force constants are discussed in terms of electronic-charge redistribution within the first layer.
40
3524
3545
Surface phonons on the Pt(111) surface: a comparison of He-scattering experiments with lattice dynamical calculations / BORTOLANI, Virginio; FRANCHINI, Anna; SANTORO, Giorgio; TOENNIES, J. P.; WOLL, C. H.; ZHANG, G.. - In: PHYSICAL REVIEW. B, CONDENSED MATTER. - ISSN 0163-1829. - STAMPA. - 40:(1989), pp. 3524-3545. [10.1103/PhysRevB.40.3524]
Bortolani, Virginio; Franchini, Anna; Santoro, Giorgio; Toennies, J. P.; Woll, C. H.; Zhang, G.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11380/452127
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