RAS investigation of benzene adsorption on vicinal singledomain Si(001)‐(2 × 1) surfaces

Abstract

We report on an experimental investigation of benzene adsorption on single-domain Si(001)-(2 × 1) by means of reflectance anisotropy spectroscopy. This optical technique is sensitive to the number of occupied dimers and permit us to demonstrate that benzene molecules are bound to slightly less than one dimer out of two.

Mechanism of Benzene Monolayer Formation on Si(100)-2×1 Studied by Surface Differential Reflectance Spectroscopy

“…Because of steric interactions along a dimer row, benzene in the BF configuration can only adsorb upon one dimer out of two (see Figure c). This result is, therefore, consistent with BF as the major grafting mode at saturation. ,,, …”

“…This result is, therefore, consistent with BF as the major grafting mode at saturation. 24,25,27,28 Let us turn now to the monolayer formation process. The increase of the integrated SDR signal, 39 measured during benzene exposure, gives access to the fraction of occupied dimers (θ dimer ) vs dose D (gray line in Figure 4a).…”

“…In this field, most of the attention has been focused on surface reactivity and the nature of the adsorbed species. For instance, as a representative model of aromatic compound adsorption, benzene adsorption on Si(100)-2×1 was extensively studied by theoretical − methods as well as experimental approaches: High-resolution electron energy loss spectroscopy (HREELS), , infrared spectroscopy, photoemission, − near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, , optical spectroscopies, thermal desorption spectroscopy (TDS), , and scanning tunneling microscopy (STM). − These studies were essentially concerned with the geometry of the adsorbed benzene. Two adsorption configurations were mainly discussed: the tight-bridge (TB) configuration that is tetra-σ bonded on two adjacent dimers (see Figure a) and the butterfly (BF) configuration that is di-σ bonded on one dimer (see Figure b,c).…”

Mechanism of hydrogen adsorption on gold nanoparticles and charge transfer probed by anisotropic surface plasmon resonance

“…This optical method is very sensitive to the surface structure and to the adsorption of atoms or molecules on anisotropic surfaces. However, it has mainly been used on flat surfaces, either in vacuum 27,[29][30][31][32] , gas 33,34 or liquid 35,36 , yet only few investigations focusing on the LSPR of supported metal NPs have been reported [37][38][39][40][41] . Recently, the LSPR of anisotropic metal NPs, synthesised by colloidal lithography and placed in a solution, have been measured using RAS 40 , which showed small LSPR shifts upon changing the refraction index of the solution or upon adsorbing molecules on the NPs.…”

A new UV reflection anisotropy spectrometer and its application to the Au(1 1 0)/electrolyte surface

“…RAS has now been established as a highly sensitive and reproducible method for identifying molecular interactions at surfaces [5][6][7][8][9][10][11][12][13]. In addition to monitoring semiconductor surfaces in which the material being studied is usually in a gaseous environment it has been used to probe the interactions of nucleic acid bases [14,15] and amino acids [16] at Au(1 1 0)/electrolyte interfaces and to monitor the adsorption of single stranded and double stranded (ss and ds) DNA at Au(1 1 0)/electrolyte interfaces [17,18].…”