Vibrations at Surfaces

This volume contains most of the invited and contributed papers presented at the second international conference devoted to the general topic "Vibrations at Surfaces" and which took place from 10 to 12 September 1980 at the Facu1tes Notre-Dame de 1a Paix in Namur, Belgium. The conference was organized to review the large amount of information gathered in this field over the late seventies as a result of th~ rapid improvements and dissemination of surface spectroscopic technique such a electron energy loss, infrared and Raman surface spectroscopies. Much time was devoted to Raman spectroscopy of adsorbed mo1e­ 'cu1es. After several years of vivid debate over the causes of the observed large enhancement of Raman cross section, a clearer pic­ ture emerges from the papers presented here: the actual value of the enhancement factor does depend in a complicated manner on long range surface roughness, atomic-scale roughness and the dielectric properties of the substrate as well as on the electronic structure of the molecule in its adsorbed state. Less controversial are the results obtained with electron energy loss spectroscopy (EELS) and several sessions of the con­ ference were devoted to the approach. As witnessed by the growing number of laboratories using the technique, EELS is now a mature spectroscopic tool for the characterization and analysis of the chemisorption bond.

1. Clean and Adsorbed Surfaces.- Theory of phonons on clean and adsorbed surfaces.- Desorption by resonant multiphoton excitation of internal adsorbate vibration.- Face centered cubic transition metal surface vibrations.- Atom motion at model crystal surfaces.- Infrared reflection absorption and emission study of methyl alcohol adsorption on MoO3 films.- Rotational accommodation at surfaces via Rayleigh phonons.- Arrangement of CO molecules adsorbed on low index metal surfaces: a comparison between LEED and HREELS or IRS.- Effects of many body forces on the adsorbate induced phonon structure.- Vibrational lifetimes for molecules adsorbed on metal surfaces.- Surface modes of a spherical void at the proximity of a surface.- Theoretical study of the vibrational properties of a (117)F. C. C. surface.- The chemisorption of CO on Cu: an ab initio cluster model study.- Librational modes of molecules on metals.- Vibrations of neutrally adsorbed atoms on transition metal surfaces.- 2. Electron energy loss spectroscopy.- EELS of surface phonons and vibrations of adsorbed species.- Electronic surface resonance enhancement of vibrational loss intensities.- EELS of collective surface modes.- The adsorption and co-adsorption with. CO of NO on Cu(110) studied with ELS and LEED.- The adsorption of H2O on Ru(001): chemisorption and hydrogen bonding.- On the excitation mechanism of vibrational modes of C2H4 chemisorbed on Pt(111) and Ni(111) by EELS.- Vibrations measured at metal surfaces by EELS: a review table.- High resolution electron spectroscopy: instrumentation and some results on a tungsten surface.- Theory of electron energy loss spectroscopy.- Adsorption sites of CO on the (111) face of Pt10Ni90 single crystal alloy.- 3. Infrared Spectroscopy.- A comparison of the reflection-absorption infrared method with the electron energy loss method for studying vibrations at surfaces.- Applications of IR ellipsometric spectroscopy to surface studies.- Reflection-absorption infrared spectroscopy using a Fourier transform spectrometer: a study of carbon monoxide adsorbed on Pt(111).- Collective vibrational modes in isotopic mixtures of CO adsorbed on Cu(100).- Intrinsic line widths of CO adsorbed on Cu(100).- “In situ” characterization of surface complexes of propene on oxidation catalysts (I. R. spectroscopy).- Infra-red cryospectroscopic study on the interaction of CO with a (111)Ni- and NaCl-film at low temperature under ultrahigh vacuum.- Infrared study of comparative adsorption of some alcohols and thiols on ?-alumina.- Infrared spectra of species adsorbed on films or well-defined surfaces: a tabulation of the investigated systems.- 4. Surface Enhanced Raman Scattering.- Surface enhanced Raman scattering from characterized metal surfaces.- Enhanced Raman spectroscopy from adsorbates on silver: evidence for the “Adatom Model”.- High resolution electron energy loss and surface enhanced Raman studies of pyridine and benzene on Ag(111).- Raman spectroscopy of thin organic films by integrated optical techniques.- Enhanced Raman scattering from molecules adsorbed at metal surfaces.- Enhanced Raman scattering from molecules adsorbed on resonant metal particles.- Enhanced Raman scattering from molecules adsorbed on small nickel particles.- Surface enhanced Raman scattering from different types of metal substrates.- The relevance of spatial variation in the electromagnetic vector potential for surface Raman scattering.- 5. Other Spectroscopies.- Adsorption of marked acetic acid on alumina studied by IETS.- The adsorption of unsaturated hydrocarbons on aluminium oxide and magnesium oxide: an inelastic electron tunnelling spectroscopy study.- Vibrations in benzene and toluene monolayers on the basal plane of graphite.- Photoacoustic and photothermal surface spectroscopy.- 6. Surface Molecular Dynamics and Reactivity.- Energy transfer processes in gas and surface reactions.- Electron-hole pairs, molecular vibrations, and rate processes at metal surfaces.- Static and dynamic aspects of chemisorption.- Vibrational activation and surface reactivity; SF6 interaction with silicon induced by infrared laser radiation.