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Кузнецов, Ан М.; Маслий, А Н; Shapnik, M. S.

doi:10.1023/a:1026607915397

Cited by 14 publications

(9 citation statements)

References 11 publications

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“…For ideal terminated Ag(111) and Au(111) surfaces, φ Ag = 428.78 kJ mol -1 54 and φ Au = 509.5 kJ mol -1 , resulting in Δ E ct = 80.7 kJ mol -1 . For water, Δ E Me - solv = −5 kJ/mol has been estimated . Differences in TU electrodesorption peak energies (Table ) from Ag(111) ( E C1 = −1.21 V) and Au(111) substrates ( E C1 = −0.83 V) 33 are Δ E C1 = −0.38 V = 36.7 kJ mol -1 in a single-electron charge-transfer process.…”

Section: Resultsmentioning

confidence: 99%

Comparative Molecular Resolution STM Imaging of Thiourea, Ethylthiourea, and Sulfur Self-Assembled Adlayer Structures on Silver (111)

et al. 2003

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Self-assembled adlayer structures of thiourea (TU), ethylthiourea (ETU), and sulfur (S) adsorbed on Ag(111), from neutral and alkaline aqueous solutions, are investigated with a scanning tunneling microscope operating under potential control. Voltammograms obtained under various different potential routines are very similar for the three substances. At potentials close to -1.2 V (versus saturated calomel electrode), a (x7×x7)R19.1°adlayer structure with superlattice and nearest neighbor distances of ds ) 0.76 nm and dn ) 0.44 nm, respectively, is imaged, irrespective of the adsorbate molecule. In this potential region, the first pair of conjugated current peaks related to electroadsorption/desorption processes is recorded. As either the electroadsorption time is increased or the applied potential is shifted positively, self-assembled TU and S monolayers evolve into more compact structures. TU adlayers compress into hexagonal arrangements with dn ) 0.33 nm, and S forms adsorbed S-trimers with the initial ordered array superstructure and coverage and shorter dn. On the other hand, ETU only presents the hexagonal arrangement with dn ) 0.44 nm common to all three adsorbates at the early ordered adsorption stages. The dynamics of adsorbate patterns can be explained by the interplay of adsorbate-substrate and adsorbateadsorbate interactions, principally hydrogen bonding for TU, steric size effects due to ethyl substituents for ETU, and a clustering process assisted by polymerization for S. As TU on Ag(111) and TU on Au(111) exhibit similar adlayer structures, the electroadsorption free energy difference was estimated from the electrodesorption voltammetric peaks. The resulting value is similar to the desorption energy differences calculated for other sulfur-containing molecules.

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Section: Resultsmentioning

confidence: 99%

Comparative Molecular Resolution STM Imaging of Thiourea, Ethylthiourea, and Sulfur Self-Assembled Adlayer Structures on Silver (111)

et al. 2003

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“…For the reductive electrodesorption of different alkanethiolates from the substrate Me in a given solvent the terms Δ E des , Δε HOMO , and Δ E S - s cancel. Therefore, the energy difference (Δ = − ) for this process is given by the n- dependent terms Note that we can neglect the n- dependent long-ranged adsorbate−substrate interactions at physisorbed micelles 20 because they are not formed in methanolic solutions . Therefore, for a given substrate, the shift in the E p value with n should reflect mainly Δ E A - s and Δ E A - A contributions.…”

Section: Discussionmentioning

confidence: 99%

Electrodesorption Potentials of Self-Assembled Alkanethiolate Monolayers on Ag(111) and Au(111). An Electrochemical, Scanning Tunneling Microscopy and Density Functional Theory Study

et al. 2002

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Molecular interactions in well characterized self-assembled alkanethiolate monolayers on Au(111) and Ag(111) are studied from reductive electrodesorption curves recorded in 0.1 M NaOH in a 95% methanol +5% water mixture to minimize the effect of hydrophobic forces. From the electrochemical and STM data and quantum DFT calculations, it can be concluded that the difference in peak potentials experimentally observed for the reductive desorption of a given alkanethiolate from the Ag(111) and Au(111) surfaces is determined by the energy to introduce an electron into the adsorbed alkanethiolate−metal species, the desorption energy of the alkanethiolate anion, and the solvent/metal interaction energy.

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“…Even though we used a mixture of 95% methanol and 5% water as electrolyte, rather than pure methanol, the adsorption energy of methanol is greater than the adsorption energy of water on these surfaces. Therefore, the use of the adsorption energy corresponding to methanol seems to be justified . To calculate E des for the alkanethiolate−copper(111) system, we have used E des = yE des , fcc + xE des,bridge (Table ) where x = 0.21 and y = 0.79 according to the site occupancy reported for methanethiolate adsorption on copper .…”

Section: Quantum Density Functional Theory (Dft) Calculationsmentioning

confidence: 99%

Electrodesorption Potentials of Self-Assembled Alkanethiolate Monolayers on Copper Electrodes. An Experimental and Theoretical Study

et al. 2003

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Electrodesorption potentials for alkanethiolate self-assembled monolayers (SAMs) on polycrystalline Cu and Cu(111) surfaces were determined by using electrochemical techniques combined with Auger electron spectroscopy. For a given alkanethiolate SAM, the electrodesorption potentials from Cu are shifted 0.6 V in the negative direction with respect to those found on Au. Calculations based on density funtional theory for methanethiolate desorption from Cu(111) show that these potential differences reflect differences in the energy for introducing an electron into the alkanethiolate−metal system and also in the energy to break the alkanethiolate S-head−metal bond. On the other hand, the alkanethiolate−alkanethiolate interaction energies at SAMs remain practically independent of the substrate.

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Cited by 14 publications

References 11 publications

Comparative Molecular Resolution STM Imaging of Thiourea, Ethylthiourea, and Sulfur Self-Assembled Adlayer Structures on Silver (111)

Comparative Molecular Resolution STM Imaging of Thiourea, Ethylthiourea, and Sulfur Self-Assembled Adlayer Structures on Silver (111)

Electrodesorption Potentials of Self-Assembled Alkanethiolate Monolayers on Ag(111) and Au(111). An Electrochemical, Scanning Tunneling Microscopy and Density Functional Theory Study

Electrodesorption Potentials of Self-Assembled Alkanethiolate Monolayers on Copper Electrodes. An Experimental and Theoretical Study

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