Physics at Surfaces

Hybrid Electrochemical/Chemical Synthesis of Quantum Dots

“…Surface scientists refer to this prompt three-dimensional growth mode as Volmer-Weber deposition. 18 Since 1996, we have found that other metals, including platinum, 19 copper, 20 nickel, 21 cadmium, 22,23 and zinc, 24 also deposit by this same VolmerWeber mechanism on graphite. Noncontact atomic force microscope (NC-AFM) images of a graphite surface following the deposition of 0.039 monolayer of platinum, for example, are shown in Figure 2a.…”

“…The image of Figure 2a also shows that platinum nanoparticles have nucleated both at defect sites such as step edges, and on atomically smooth terraces. Volmer-Weber growth is favored at coordinatively saturated surfaces, like graphite, that are characterized by a low interfacial free energy 18 (35 dyn cm -1 in the case of the graphite basal plane 25 ). Becca Stiger has demonstrated 26 that the Volmer-Weber deposition mechanism also operates at another low-energy surface: that of hydrogen-terminated Si(100).…”

Electronic structure of octane on Cu(1 1 1) and Ni(1 1 1) studied by near edge X-ray absorption fine structure

“…Here, ϕ i is the wave function of the 1s orbital and ϕ f is the π* or σ* molecular orbital. Equation (1) indicates that the value of μ is greatest for E along the molecular orbital, while μ becomes zero for E perpendicular to the orbital. Since the σ* molecular orbital is parallel to the molecular long axis, the 1s→σ*(C-C) transitions occur for E parallel to the molecular long axis.…”

“…Since the σ* molecular orbital is parallel to the molecular long axis, the 1s→σ*(C-C) transitions occur for E parallel to the molecular long axis. The molecular orientation angle was quantitatively evaluated by fitting the intensity of the peaks to the theoretical curves obtained by equation (1). Using the polarization dependence of the σ*(C-C) peak, the mean inclination angle of the octane molecules from the surface was determined to be 15(±10)° on both substrates (lying-down configuration).…”

“…The interaction between alkanes and metals has attracted wide attention [1][2][3][4][5]. This is due to the fact that many catalytic processes involve the conversion of saturated hydrocarbons to various products, and also because n-alkane is the simplest molecule among the saturated hydrocarbons.…”