Observation of a change of vibrational excitation mechanism with surface temperature: HCl collisions with Au(111)

We have measured the vibrational excitation probability (Pv) of HCl incident on a Au(111) surface at kinetic energies (Ei) of 0.59 eV to 1.37 eV and surface temperatures (Ts) of 273 K to 1073 K. For all energies, the slope of the Pv as a function of Ts exhibits a sharp increase above Ts approximately 800 K. We show this change in slope and the threshold behavior of Pv to be consistent with a change in excitation mechanism from an electronically adiabatic mechanical mechanism to an electronically nonadiabatic mechanism involving excited electron-hole pairs.     

Observation of vibrational excitation and deexcitation for NO (v = 2) scattering from au(111): evidence for electron-hole-pair mediated energy transfer

Measurements of vibrational excitation and deexcitation of NO (v = 2) scattering from a Au(111) surface show that the probability of both processes increases strongly with the kinetic energy of the incident NO. These results are qualitatively consistent with a vibrational energy transfer mechanism involving electron-hole pairs but not with competing adiabatic models. The form of the energy dependence, and other features of the measurements, are not in accord with existing calculations.     

Dislocations on Ag(111)

Various dislocations on Ag(111) were imaged with a scanning tunneling microscope, e.g. screw dislocations, Lomer-Cottrell locks and stacking fault tetrahedron. The distortion field near a screw dislocation was measured.     

Observation of surface plasmon splitting on Ag(111) by electroreflectance spectroscopy

The spectral dependence of electroreflectance near the surface plasma frequency of Ag(111) has been measured for various degrees of surface roughness. The experiments clearly show a splitting of the surface plasma resonance on increasing the roughness of the sample. The results agree well with a recent theory which predicts a splitting of the surface plasmon dispersion relation on a statistically rough surface.     

Xe adsorption on Ag(111): Experiment

Precise structural and thermodynamic studies of Xe adsorbed on Ag(111) are made using low-energy diffraction. Spacings are measured relative to those of bulk adsorbed film. Effective equilibrium experiments are done using a directed gas beam and cryopumping. The density of only that gas in the coherently diffracting area is measured by the attenuation of the Ag(01) beam. With decreasing temperature at fixed gas flux one observes the sequential of 2D gas, monolayer, bilayer and bulk films. The effective pressure of the impinging gas is determined from the known bulk vapor pressure so bypassing absolute pressure measurements. The phase diagram, lattice spacings in the film at equilibrium and at zero pressure, latent heats of adsorption and isosteric heats are determined.     

The Tamm surface state on Cu(111) and Ag(111)

It is shown, that the well-known d-electron Tamm surface-state emission observed in photoelectron spectra from Cu(111) at the M̄ point in the surface Brillouin zone, is indeed due to such a surface state and not a bulk band transition as recently suggested L. Wallden, Solid State Commun. 59, 205 (1986). A similar surface state on Ag(111) is reported.     

Ag(111)和Au(111)上铋的初始生长行为

半金属铋(Bi)的表面合金具有的Rashba效应,和其具体结构性质有重要关联.本文结合扫描隧道显微镜(STM)和密度泛函理论(DFT),系统地研究了Bi原子在Ag(111)和Au(111)上的不同初始生长行为.在室温Ag(111)上,连续的Ag2Bi合金薄膜会优先在Ag台阶边缘形成;在570 K Ag(111)上,随着...