Coverage-dependent frequency for Li-atom vibrations on Cu(111)

Journal Article · Tue Oct 01 04:00:00 EDT 1996 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.54.10912· OSTI ID:389311

Lindgren, S; Svensson, C; Wallden, L; Carlsson, A; Wahlstroem, E ^[1]

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1. Physics Department, Chalmers University of Technology, Goeteborg (Sweden)

Electron-energy-loss spectra recorded for monolayer amounts of Li adsorbed on Cu(111) show a loss peak associated with Li vibrations perpendicular to the substrate. The loss energy shifts from 38 meV at low coverage to 43 meV at 0.3 ML and remains constant for coverages between 0.3 and 0.5 ML. The loss intensity passes a maximum at a Li coverage of 0.15 ML and gradually decreases such that it is difficult to resolve a loss peak at coverages above 0.5 ML. The high loss energy indicates that the adatom resides on the surfaces rather than in substitutional sites. The frequency shift is much too large to be explained by dipole-dipole interactions. The above results are obtained with the evaporation source loaded with the natural Li isotope mixture (92.6{percent} {sup 7}Li, 7.4{percent} {sup 6}Li). Measurements with {sup 6}Li show that the increase of the vibration frequency with increasing coverage is not an isotope effect. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 389311
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 15 Vol. 54; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
CHEMICAL BONDS
CHEMISORPTION
COPPER
ELECTRONIC STRUCTURE
ENERGY-LOSS SPECTROSCOPY
ISOTOPE EFFECTS
LITHIUM
TEMPERATURE RANGE 0065-0273 K
VIBRATIONAL STATES