Effects of methyl substitution on room-temperature chemisorption of para-xylene on Si(100)2×1 and modified surfaces: a thermal desorption and DFT study

Chemical manipulation of multifunctional hydrocarbons on silicon surfaces

“…The chemical reactivity of the methyl group in toluene was supported by the first principles calculation studies by Costanzo et al [12,13]. A study by Li et al employed a combination of low-energy electron diffraction (LEED), Auger electron spectroscopy (AES), thermal desorption, and DFT calculations to specifically examine the adsorption of para-xylene (1, 4-dimethylbenzene) and noted that this hydrocarbon adsorbs very similarly to benzene on the Si(100)-2×1 substrate [114]. In a contrast with the studies of Coulter et al [113], no vibrational spectroscopy investigation was undertaken by this group; however, a deuterium-substitution approach confirmed that while some of para-xylene molecules desorb intact at 400 and 470 K (from two different geometries of surface adducts), the majority of these molecules are strongly chemisorbed after the loss of hydrogen from methyl groups [114].…”