n-alkyl thiol head-group interactions with the Au(111) surface

Abstract

State-of-the-art first principles calculations based on density functional theory were performed on CH 3 (CH 2 ) n−1 S-Au(111) systems. We show that the adsorption site of methylthiolate at low coverage on the Au(111) surface is the fcc site, not the hcp site as has been recently reported. Further, we report results for chain length dependency and the electronic structure of the system.The interaction between organic materials and solid surfaces has been extensively studied because of the broad range of industrial applications. 1-4 Self-assembled monolayers (SAMs) hold special interest, because the presence of the thiol group greatly strengthens the molecule-surface interactions, inducing order in the layer. SAMs have important potential applications in industry, such as sensors, transducers, detectors, packaging and insulating layers for integrated circuits, functionalization of surfaces, thin coatings for electrodes, and corrosion inhibition.The long-chain alkane thiols [CH 3 (CH 2 ) n−1 SH, or C n ] form SAMs on the Au(111) surface. Their simplicity, highly ordered structures, and chemical stability make these systems ideal for study with a variety of techniques including atomic force microscopy, 5,6 infrared spectroscopy, 7,8 high-resolution electron-energy-loss spectroscopy, 9 grazing X-ray diffraction, 10 scanning tunneling microscopy (STM), 11-17 scanning probe microscopy, 18 lowenergy electron diffraction (LEED), [19][20][21] He atom diffraction, 22,23 and theory. 25-31 Despite 1

Thiolate adsorption on Au(${\bm {hkl}}$hkl) and equilibrium shape of large thiolate-covered gold nanoparticles

“…Similarly, Maksymovych et al 47 found a binding energy of −1.77 eV for (b) and a bond length of 2.45 Å for the same adsorption geometry. Masens et al 9 report an adsorption energy of −1.70 eV for (b) close to −1.73 eV found by Yourdshahyan et al 5 In case (c), Zhou and Hagelberg 10 report a dissociative adsorption energy of −0.06 eV, but they conclude that the adsorption of the methanethiol is nondissociative since the nondissociative structure of methanthiol displays a higher adsorption energy than the dissociative one by 0.6 eV. They also found the Au-S bond length to be 2.45 Å.…”

“…Several groups have studied methanethiolate adsorption on Au(111) both experimentally 47 and theoretically. 3,[5][6][7][8][9][10]47 In these studies, the following four reactions are considered: a. dissociative adsorption of CH 3 S-SCH 3 , b. adsorption of CH 3 S radical, c. dissociative adsorption of CH 3 S−H, and d. same as (c), but H is desorbed as H 2 .…”

“…The majority of them investigates the adsorption energy of CH 3 S-radical on Au(111). [3][4][5][6][7][8][9][10][11][12] Various groups have studied the dissociative adsorption of dimethyl disulfide (DMDS) on Au(111), both theoretically 3,11 and experimentally. [13][14][15] In particular, Nuzzo et al 13 suggested, after employing a large variety of experimental methods including X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), high-resolution electron energy loss spectroscopy (HREELS), and thermal desorption spectroscopy (TDS), that the breaking of the (weak) S-S bond of DMDS leads to the formation of a) Electronic mail: barmparis@materials.uoc.gr.…”

The effect of surface symmetry on the adsorption energetics of SCH3 on gold surfaces studied using Density Functional Theory

“…First principles and semi-empirical studies can map the potential energy surface of the gold-thiolate molecular interaction and identify preferred adsorption geometries and binding energies. The literature contains a number of such studies [17] [18][19][20][21], but has generally followed the experimental lead and been confined to the Au(111) surface.…”

The electronic and transport properties of a molecular junction studied by an integrated piecewise thermal equilibrium approach

“…Chen et al [30] obtained an Au-S bond length of 2.37Å and an Au-S-C bond angle of 102.8 o for the Au-atom-BDT-Au-atom molecule. In comparison, Yourdshahyan, Zhang and Rappe obtained a much larger Au-S-C bond angle between 132° and 138° for the long-chain alkane thiols [CH 3 (CH 2 ) n-1 SH] chemisorbed on the Au(111) surface [59]. The calculated partial densities of states (PDOS) of S and C atoms and the Au atoms that are bonded with the S atoms are shown in Fig.…”