The influence of coadsorbed sodium atoms on the chemisorption of benzoic acid on Si(100)-2×1

Abstract The adsorption of benzoic acid on Na–Si(100)-2×1 ( Θ Na =0.5) at room temperature leads to benzoate in a bidentate coordination. High-resolution electron energy loss spectroscopy spectra show an intense ν s (OCO) stretching vibration, which is characteristic for benzoate aligned perpendicular to the substrate surface. In contrast, we observe monodentate benzoate species following the exposure of Si(100)-2×1 to benzoic acid at room temperature. On both surfaces, the dissociated hydrogen atom bonds to one of the silicon surface atoms. Removal of benzoate from Na–Si(100)-2×1 is observed after heating the silicon substrate to 300°C for 1 min.