Manipulating the orientation of an organic adsorbate on silicon: a   NEXAFS study of acetophenone on Si(001)
  We investigate the chemical and structural configuration of acetophenone on Si(001) using synchrotron radiation core-level spectroscopy techniques and density functional theory calculations. Samples were prepared by vapour phase dosing of clean Si(001) surfaces with acetophenone in ultrahigh vacuum. Near edge X-ray adsorption fine structure spectroscopy and photoelectron spectroscopy measurements were made at room temperature as a function of coverage density and post-deposition anneal temperature. We show that the dominant room temperature adsorption structure lies flat on the substrate, while moderate thermal annealing induces the breaking of Si-C bonds between the phenyl ring and the surface resulting in the reorientation of the adsorbate into an upright configuration. 
Kane M. O'Donnell, Oliver Warschkow, Asif Suleman, Adam Fahy, Lars   Thomsen and Steven R. Schofield
cond-mat.mtrl-sci