Chemisorption of acetic acid onSi(100)−2×1at room temperature

We have investigated adsorption of acetic acid on $\mathrm{Si}\left(100\right)\text{−}2\times 1$ at room temperature using high-resolution photoemission spectroscopy and near edge x-ray adsorption fine structure (NEXAFS) measurements in the partial electron yield mode. At room temperature, an acetic-acid molecule is found to chemisorb on $\mathrm{Si}\left(100\right)\text{−}2\times 1$ surface through the formation of the $\mathrm{O}\mathrm{H}$ dissociation structure. NEXAFS was conducted to characterize the adsorption geometry of acetic acid on Si(100). The ${\pi }^{*}$ orbital of the $\mathrm{C}\mathrm{O}$ bond shows a good angle dependence in carbon $K$-edge NEXAFS spectra, and we estimate the adsorption angle between chemisorbed acetic acid of $\mathrm{C}\mathrm{O}$ bond and the Si(100) surface normal as $\sim 41°\pm 2°$ using an analytical solution of NEXAFS intensity.