Electronic Raman scattering at disordered noble- and alkali-metal surfaces

Abstract Electronic Raman spectra with continuous Stokes shifts between 250 cm−1 and 3500 cm−1 are observed from potassium and noble-metal films of thickness 150 nm grown on a smooth substrate at 40 K in ultrahigh vacuum. We investigate the irreversible transformation of the spectra during thermal annealing of the surface structure. In the case of potassium, the Raman yield shows a continuous decline upon annealing from 40 K to 300 K, roughly following the photoelectron yield. In the case of silver we observe a decrease in halfwidth by a factor of 2 and an increase of the peak intensity by a factor of 10 upon annealing to 250 K. This behaviour of silver is explained by intraband excitations of the electronic surface state at (111) facets. The observations are, in principal, in agreement with an evaluation of the transition phase space.

[1]  A. Otto,et al.  Continuous secondary light emission from silver films: on the origin of the inelastic background in SERS , 1994 .

[2]  M F Crommie,et al.  Confinement of Electrons to Quantum Corrals on a Metal Surface , 1993, Science.

[3]  D. Eigler,et al.  Imaging standing waves in a two-dimensional electron gas , 1993, Nature.

[4]  A. Otto,et al.  D.C. resistivity variation of cold-deposited silver films during gas exposure , 1990 .

[5]  A. Mal’shukov,et al.  The nature of the inelastic background in surface enhanced raman scattering spectra of coldly-deposited silver films. The role of active sites , 1989 .

[6]  A. Otto,et al.  On the optical properties of coldly deposited silver films: Comparison of eels and reflectivity spectra , 1988 .

[7]  F. Fischer,et al.  Additional Results on SERS from Ag Colloids in Alkali Halide Crystals , 1987 .

[8]  F. Flores,et al.  Raman Scattering by Electron-Hole Pairs at Metal Surfaces , 1987 .

[9]  Shen,et al.  Photoinduced luminescence from the noble metals and its enhancement on roughened surfaces. , 1986, Physical review. B, Condensed matter.

[10]  A. Goldmann,et al.  On the annealing of “sers active” silver films: UPS and TDS of adsorbed xenon , 1986 .

[11]  Riess,et al.  Hydrogenic image-potential states: A critical examination. , 1986, Physical review. B, Condensed matter.

[12]  H. Fukuda,et al.  An Application of Surface-Enhanced Raman Scattering to the Surface Characterization of Carbon Materials , 1986 .

[13]  Goldman,et al.  Erratum: Empty electronic states at the (100), (110), and (111) surfaces of nickel, copper, and silver , 1985, Physical review. B, Condensed matter.

[14]  C. Pettenkofer,et al.  “Sers Activity” of Coldly Deposited Ag and Cu Films Quenched by Oxygen , 1986 .

[15]  James K. Gimzewski,et al.  A comparative study of coldly-and warmly-condensed Ag films by scanning tunneling microscopy , 1985 .

[16]  Ezequiel V. Albano,et al.  On the porosity of coldly condensed sers active Ag films: II. Comparison of adsorption and Raman scattering of pyridine , 1985 .

[17]  A. Otto.  Surface enhanced Raman scattering , 1983 .

[18]  S. Kevan.  Evidence for a new broadening mechanism in angle-resolved photoemission from Cu(111) , 1983 .

[19]  Manuel Cardona,et al.  Light Scattering in Solids VII , 1982 .

[20]  I. Pockrand,et al.  Surface enhanced Raman scattering (SERS): Annealing the silver substrate , 1981 .

[21]  A. Otto,et al.  Enhanced raman effect from cyanide adsorbed on a silver electrode , 1980 .

[22]  J. M. Worlock,et al.  Surface picosecond raman gain spectroscopy of a cyanide monolayer on silver , 1979 .

[23]  C. Y. Chen,et al.  Giant Raman scattering by pyridine and CN− adsorbed on silver , 1979 .

[24]  F. Himpsel,et al.  Observation of a Λ 1 -Symmetry Surface State on Ni(111) , 1978 .

[25]  A. Otto,et al.  Raman spectra of (CN) - adsorbed at a silver surface , 1978 .

[26]  S. A. Flodström,et al.  Angular-resolved photoemission from low-index crystal faces of silver—bulk and surface contributions , 1978 .

[27]  P. Heimann,et al.  Ultraviolet photoemission for intrinsic surface states of the noble metals , 1977 .

[28]  P. Winsemius,et al.  Temperature dependence of the optical properties of Au, Ag and Cu , 1976 .

[29]  M. Klein,et al.  Electronic Raman scattering and the metal-insulator transition in doped silicon , 1976 .

[30]  W. Sachtler,et al.  Photoelectric emission and phase transitions of evaporated metastable sodium, potassium and sodium-potassium alloy films , 1972 .

[31]  A. Mooradian,et al.  Photoluminescence of Metals , 1969 .