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Time dependent density functional theory study of the near-edge x-ray absorption fine structure of benzene in gas phase and on metal surfaces J. Chem. Phys. 129, 064705 (2008); 10.1063/1.2967190Effect of self-assembled monolayer film order on nanofriction Dipole-induced structure in aromatic-terminated self-assembled monolayers-A study by near edge x-ray absorption fine structure spectroscopyNear edge x-ray absorption fine structure spectroscopy ͑NEXAFS͒ was used to investigate contact-printed ͑CP͒, self-assembled monolayers ͑SAMs͒ of alkanethiols on gold. We studied the influence on order and orientation of the alkyl chains of both the chain length of the thiols and the concentration of the inking solution that was used for stamping. The results are compared to those for monolayers prepared by the conventional technique of immersing the substrate into solution. Our study shows that the CP process, when performed with a sufficiently concentrated solution of the thiol, can result in monolayers indistinguishable from those established by immersion into solution, independent of the thiol chain length. For lower concentrations, however, CP monolayers show a significant deviation from well-ordered films and have to be classified as mainly disordered. As with SAMs prepared from solution, shorter chains ͑dodecanethiol͒ lead to a lower degree of order compared to longer ones ͑hexadecanethiol͒, which can be attributed to their relatively higher percentage of gauche conformations at room temperature. Nevertheless, with lateral force microscopy a slight contrast is still observable between immersed and microcontact-printed ͑CP͒ areas of well-ordered films, as has been previously reported by other groups and attributed to slight differences in the packing density of the chains in the differently prepared regions of the final layer. On the basis of our NEXAFS data the difference of gauche defects due to different average packing densities in the resulting layers can be estimated to be less than 30%.