TY - JOUR
T1 - Collective vibrational modes of the high-density (1 × 1)-O phase on Ru(001)
AU - Moritz, T.
AU - Menzel, D.
AU - Widdra, W.
N1 - Funding Information:
This work was supported by the Deutsche Forschungsgemeinschaft through SFB 338.
PY - 1999/6/1
Y1 - 1999/6/1
N2 - High-resolution electron energy-loss spectroscopy (HREELS) has been used to investigate the vibrational properties of the newly discovered, well-ordered oxygen (1 × 1) overlayer on Ru(001). The totally symmetric Ru-O stretch has been mapped out along the Γ̄-K̄-M̄-K̄direction of the surface Brillouin zone (SBZ). The stretching mode exhibits a strong downward dispersion of about 100 cm-1 along Γ̄-K̄ starting at 660 cm-1, with a subsequent upward dispersion along K̄-M̄. The dispersion observed for small k∥ is explained by dominating long-range dynamical dipole-dipole coupling. From comparisons of experimental data in the vicinity of the Γ̄ point with calculations for dipole-dipole coupling, the frequency of the isolated oscillator (singleton frequency), as well as the vibrational and electronic polarizabilities, can be estimated to be 598 cm-1, 0.8 angstrom3 and 1.7 angstrom3, respectively. However, the short-range interactions deviate significantly from dynamical dipole-dipole interactions as is documented by the discrepancy between the calculated and the observed dispersion between K̄ and M̄.
AB - High-resolution electron energy-loss spectroscopy (HREELS) has been used to investigate the vibrational properties of the newly discovered, well-ordered oxygen (1 × 1) overlayer on Ru(001). The totally symmetric Ru-O stretch has been mapped out along the Γ̄-K̄-M̄-K̄direction of the surface Brillouin zone (SBZ). The stretching mode exhibits a strong downward dispersion of about 100 cm-1 along Γ̄-K̄ starting at 660 cm-1, with a subsequent upward dispersion along K̄-M̄. The dispersion observed for small k∥ is explained by dominating long-range dynamical dipole-dipole coupling. From comparisons of experimental data in the vicinity of the Γ̄ point with calculations for dipole-dipole coupling, the frequency of the isolated oscillator (singleton frequency), as well as the vibrational and electronic polarizabilities, can be estimated to be 598 cm-1, 0.8 angstrom3 and 1.7 angstrom3, respectively. However, the short-range interactions deviate significantly from dynamical dipole-dipole interactions as is documented by the discrepancy between the calculated and the observed dispersion between K̄ and M̄.
UR - http://www.scopus.com/inward/record.url?scp=2942638981&partnerID=8YFLogxK
U2 - 10.1016/S0039-6028(99)00234-4
DO - 10.1016/S0039-6028(99)00234-4
M3 - Conference article
AN - SCOPUS:2942638981
SN - 0039-6028
VL - 427-428
SP - 64
EP - 68
JO - Surface Science
JF - Surface Science
T2 - Proceedings of the 1998 9th International Conference on Vibrations at Surfaces (VAS9)
Y2 - 12 October 1998 through 16 October 1998
ER -