Abstract
The adsorption of acetone [(CH3)(2)CO] on the Si(001) surface has been investigated using density functional theory (DFT) and scanning tunneling microscopy (STM). Three distinct features have been observed in the experimental STM images - one single-dimer and two two-dimer wide features. We have considered 32 different possible adsorbate configurations corresponding to the [2+2] cycloaddition, dative bonded, a-Hydrogen cleavage, C-H bond cleavage, methyl cleavage, cross-dimer bridging, O-dimer insertion, OH cleavage, alcohol-like, end-bridging and dimer-bridging structures. The optimised geometry, binding energy, and simulated filled- and empty-state STM images for each of these possible configurations are presented. These results have facilitated the identification of the three experimentally-observed acetone adsorbate structures. (C) 2008 Elsevier B.V. All rights reserved.