The RAS of two monolayers of Pd deposited on the Au(110)1 × 2 surface

Abstract

We compare the RAS of the Au(110)1x2 surface and the RAS of surfaces formed by depositing and then annealing two monolayers of Pd deposited on the Au(110)1x2 surface. The similarities and differences between the RAS of the Au(110) 1x2 surface and the annealed Pd/Au(110) surface are consistent with the view that annealing gives rise to the formation of a Au overlayer on top of a mixed Pd/Au layer. The RAS suggests that the Au overlayer gives rise to the surface states found on the Au(110) 1x2 surface.

The Structure of Adenine Adsorbed at Sub-Saturation Coverage at Au(110)/Electrolyte Interfaces

“…The RAS profiles of the Au(110) surfaces shown in Fig. 1(a) are very similar to the RAS profile obtained in the earlier work [1] and to RAS profiles of Au(110) 2×1 surfaces obtained in other studies in both electrochemical [2,11] and ultra high vacuum environments [12][13][14][15]. The interpretations of the origin of the spectral features in the RAS profile of this surface have been reviewed in detail [2].…”

Determination of the structure of adenine monolayers adsorbed at Au(110)/electrolyte interfaces using reflection anisotropy spectroscopy

“…7 The flame annealing procedure that was adopted for the preparation of the surfaces is known to lead to a ͑1 ϫ 2͒ missing row reconstruction in an electrochemical environment at a potential of 0.0 V. 31 Previous work 7 indicates that the RAS of the Au͑110͒ ͑1 ϫ 2͒ surface in the spectral region of 1.5 eV to just beyond the sharp negative peak at 2.6 eV is extremely sensitive to the surface layer and has a major contribution from transitions involving surface states. 7,13,38,[40][41][42][43][44] An analysis in terms of a derivative model by Martin et al 45 has established that the RAS of the Au͑110͒ ͑1 ϫ 2͒ surface in the spectral region of 2.5-4.5 eV is dominated by transitions between bulk band states that are modified by the surface structure. It is also clear from these studies that the negative peak at 3.5 eV is less sensitive to the surface structure than the 2.6 eV peak and that the positive feature to high energy is associated with the presence of monatomic steps aligned along the ͓110͔ direction.…”

“…However, the RAS of the Au͑110͒ surface in both UHV and electrochemical environments has been analyzed in terms of a number of empirical phenomenological models and some insight into the character of the various spectral features has been obtained from studies of the deposition of Cu and Pd on the Au͑110͒ surface. 7,[38][39][40][41] The conclusions of the studies employing empirical models have been reviewed in detail. 7 The flame annealing procedure that was adopted for the preparation of the surfaces is known to lead to a ͑1 ϫ 2͒ missing row reconstruction in an electrochemical environment at a potential of 0.0 V. 31 Previous work 7 indicates that the RAS of the Au͑110͒ ͑1 ϫ 2͒ surface in the spectral region of 1.5 eV to just beyond the sharp negative peak at 2.6 eV is extremely sensitive to the surface layer and has a major contribution from transitions involving surface states.…”

Observation of the Electrochemical Oxidation of Au(110) by Reflection Anisotropy Spectroscopy

“…21 The calculation of RA spectra from first principles is very challenging and such calculations have not been performed for the Au͑110͒ surface. The analysis of the RA spectra of Au͑110͒ surfaces in terms of a number of phenomenological models has been reviewed in detail, 14 and some insight into the origin of spectral features has been obtained from studies of the effects of the deposition of Pd onto Au͑110͒ in UHV 39 and the underpotential deposition of Cu on Au͑110͒ in an electrochemical cell. 33 These and other studies indicate that the RAS of the Au͑110͒ ͑1 ϫ 2͒ surface in the spectral region 1.5 eV to just beyond the sharp negative peak at 2.6 eV is extremely sensitive to the surface layer and has a major contribution from transitions involving surface states.…”

“…One of the surface states involved is close to the Fermi energy. 14,18,30,33,[39][40][41] An analysis in terms of a derivative model by Martin et al 42 has established that the RAS of the Au͑110͒ ͑1 ϫ 2͒ surface in the spectral region 2.5-4.5 eV is dominated by transitions between bulk band states that are modified by the surface structure. It is also clear from these studies that the negative peak at 3.5 eV is less sensitive to the surface structure than the 2.5 eV peak and that the positive feature to high energy is associated with the presence of monoatomic steps in the ͓11 ¯0͔ direction.…”