Reconstruction of Cu(111) Induced by a Hyperthermal Oxygen Molecular Beam

Abstract

This paper reports a study on the surface reconstruction on Cu(111) induced by a hyperthermal oxygen molecular beam (HOMB) at room temperature (RT). HOMB incidence at translational energies (E i ) g 0.5 eV induced surface reconstruction to the | -1 3 2 2 | structure for an O coverage (Θ) g 0.27 monolayer (ML). On the other hand, long-range-ordered structures were not formed even at Θ ≈ 0.4 ML for the backfilling of thermal O 2 at RT. No surface reconstruction was induced at E i e 0.23 eV where the attainable Θ value was 0.27 ML for the O 2 exposures below 10 18 molecules/cm 2 . Translational energy above 0.5 eV is required for the dissociative adsorption of O 2 and the resulting surface reconstruction at Θ g 0.27 ML. The O-1s XPS peak for HOMB incidence at RT was resolved into two components, 529.4 and 528.9 eV, at Θ g 0.27 ML, which can be assigned to the O atoms occupying the three-fold hollow sites on unreconstructed Cu(111) and four-coordinated sites on the | -1 3 2 2 | structure, respectively. Annealing the | -1 3 2 2 | reconstructed surface at 620 K decreased Θ to ∼0.27 ML and induced (√13R46.1°× 7R21.8°), the so-called "29" superstructure.

Probing adsorption sites for CO on ceria

“…[31][32][33][34][35] These chemisorbed oxygen atoms occupy three-fold hollow sites on Cu(111) and cause the lateral expansion of the Cu lattice. [31][32][33][34][35] These chemisorbed oxygen atoms occupy three-fold hollow sites on Cu(111) and cause the lateral expansion of the Cu lattice.…”

Re-visiting the O/Cu(111) system – when metastable surface oxides could become an issue!

“…In this work, we analyze the stability and population of the structure observed by Moritani et al 15 using first-principles theory and we discuss this structure with respect to the known low-energy partially oxidized p4 structures and in comparison with the Cu 2 O (110) surface.…”

“…Considering the close-packed Cu(111) surface, there is general agreement that oxidation of Cu(111) can lead to substantial reconstruction, up to bulk oxide formation at the surface. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Clearly, the nature and stability of different partially oxidized surface terminations depend on ambient conditions like partial pressure of the surrounding oxygen gas atmosphere and temperature. In an ab initio theoretical study it has been shown that at conditions typical of technical catalysis, the bulk oxide is thermodynamically most stable, followed in the surface energy hierarchy by a thin surface oxide structure.…”

“…Using a combination of XPS and LEED measurements at room temperature, Moritani et al showed that exposing the Cu(111) surface to a hyperthermal oxygen molecular beam leads to adsorbateinduced surface reconstruction to a | 3 2 −1 2 | structure for an oxygen coverage ≥ 0.27 monolayer and translational energies of oxygen ≥ 0.5 eV. 15 This structure is not observed, if the incoming oxygen molecules have lower energies. It is argued that for the formation of the | 3 2 −1 2 | superstructure, it is crucial that the energy of incoming O 2 molecules is large enough to overcome the barrier for dissociative adsorption of O 2 at the Cu(111) surface, where the calculated activation barrier for the dissociation is 0.2 eV.…”

Preferential Sputtering of DNA Molecules on a Graphite Surface by Ar Cluster Ion Beam

“…Thus, such low-energy particles can induce these surface reactions. [20][21][22][23][24] However, energies of several electronvolts are significantly lower than the energy required for sputtering, 25,26 which indicates that, by controlling the cluster size and impact energy, the surface reaction can be controlled without damaging the substrate surface. Therefore, size-selected gas cluster ion beams (SS-GCIBs) are of great interest for practical applications in nanofabrication and also as cluster projectiles for SIMS.…”