Showing papers by "Thalappil Pradeep published in 1998"
TL;DR: The difference in adsorbate geometry is presumably due to the changes in interaction and not to differences in the lattice constants of the two surfaces, which is rather small as discussed by the authors.
Abstract: 1,4-Benzenedimethanethiol (HS−CH2−C6H4−CH2−SH, BDMT) adsorbs dissociatively on silver and gold surfaces yielding self-assembled monolayers with the thiolate structure. Whereas the molecule adsorbs flat on silver as a result of the loss of two thiol protons, it adsorbs with the molecular plane perpendicular to the gold surface with the loss of one thiol proton. This is manifested by the presence of the ring C−H and S−H stretches and the S−C−H bend for the Au monolayer and the absence of these for the Ag monolayer in the surface-enhanced Raman spectra. The difference in adsorbate geometry is presumably due to the changes in interaction and not to differences in the lattice constants of the two surfaces, which is rather small. In both cases, metal−adsorbate π bonding is weak, resulting in only small shifts in the ring modes. BDMT monolayers are more stable than alkanethiol monolayers and desorb only at a fairly high temperature of 423 K in air, whereas alkanethiols desorb below 373 K. An increase in temperat...
108 citations
TL;DR: In this paper, the formation of self-assembly of polycrystalline gold monolayers has been investigated using FT-Raman spectroscopy using CH3(CH2)n SH (n = 2, 5, 7, 8, 9, 11 and 17).
36 citations
TL;DR: In this article, X-ray photoelectron spectroscopy was used to study self-assembled monolayers of varying chain lengths and the binding energies and peak shapes were determined for all the samples.
25 citations
TL;DR: In this paper, a gas-phase reaction of W-, Si-, P-, Br-, and I-containing ions with the target molecule perfluorohexane at low collision energies (15 eV) parallel known ion/surface reactions of the same projectile ions at fluorinated self-assembled monolayer surfaces.
12 citations
TL;DR: In this article, a simple method for the preparation of surface-enhanced Raman-active gold films is reported, which involves sputter coating of gold to about 2000 A thickness on oxidized aluminium foils which yield surfaces of sub-micrometre roughness.
Abstract: A simple method for the preparation of surface-enhanced Raman-active gold films is reported. The method involves sputter coating of gold to about 2000 A thickness on oxidized aluminium foils which yield surfaces of sub-micrometre roughness. Self-assembled monolayers of thiols grown on these substrates yield good-quality Raman spectra. Monolayers with different functionalities have also been characterized by Raman scattering. © 1998 John Wiley & Sons, Ltd.
10 citations