<i>c</i>(4 × 2) Structures of Alkanethiol Monolayers on Au (111) Compatible with the Constraint of Dense Packing

Voznyy, Oleksandr; Dubowski, Jan J.

doi:10.1021/la8043347

Cited by 35 publications

(54 citation statements)

References 51 publications

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“…We note that the results from the core-level spectroscopy conform to the energetic argument in the preference for the MeS-Au-SMe structure over alternative adsorption models. 22 It is also consistent with experimental STM, 23 IR, 24 GIXRD, 25 and NEXAFS ͑Ref. 26͒ data.…”

Section: Discussionsupporting

confidence: 78%

“…22 Although there is an uncertainty concerning the ability of state-of-the-art DFT methods to predict small energy differences ͓in particular, for reconstructed RS / Au͑111͒ systems, as the cohesive energy of gold is underestimated by ϳ15%͔ the structure based on RS-Au-RS units is consistent with the bulk of experimental data. RS-Au-SR complexes bonded to Au͑111͒ has been observed at different coverages by STM, 23 calculations of the infrared ͑IR͒ vibrational signatures match the experimental data, 24 simulations of the GIXRD maps 25 are in agreement with experiments and calculations for the RS-Au-RS structure compare favorably with sulfur K-edge near-edge x-ray absorption fine-structure ͑NEXAFS͒ measurement. 26 It has also been suggested that the RS-Au-RS structure might be consistent with normal-incidence XSW data.…”

Section: Introductionsupporting

confidence: 72%

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Photoemission core-level shifts reveal the thiolate-Au(111) interface

Grönbeck

Odelius

2010

Phys. Rev. B

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Section: Discussionsupporting

confidence: 78%

Section: Introductionsupporting

confidence: 72%

Photoemission core-level shifts reveal the thiolate-Au(111) interface

Grönbeck

Odelius

2010

Phys. Rev. B

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“…[10][11][12][13][14][15]. These potential applications of SAMs of thiols on gold surface motivate many researchers to explore the nature of adsorbed species, site of adsorption and the nature of interaction between adsorbed species and the gold surface using experimental and theoretical investigations [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54]. Earlier experimental and theoretical report suggested that the SAMs of methylthiol preferred to adopt a (H3 9 H3)R30°s tructure and may manifest c(2 9 4) superstructure upon varying the chain length; the S head group seems to predominately attack the fcc (face-centered cubic) site of Au (111) surface [16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

On the kinetics and thermodynamics of S–X (X = H, CH3, SCH3, COCH3, and CN) cleavage in the formation of self-assembled monolayers of alkylthiols on Au(111)

Jaccob¹,

Rajaraman²,

Totti³

2012

Theor Chem Acc

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Abounding potential technological applications is one of the many reasons why adsorption of aliphatic thiols on gold surface is a subject of intense research by many research groups. Understanding and exploring the nature of adsorbed species, the site of adsorption and the nature of interaction between adsorbed species and the gold surface using experimental and theoretical investigations is an active area of pursuit. However, despite a large number of investigations to understand the atomistic structures of thiols on Au(111), some of the basic issues are still unaddressed. For instance, there is still no clear information about the mechanism of adsorption of alkylthiol on gold surface. Furthermore, the reactivity and mechanism of adsorption of alkylthiol is likely to differ when gold adatoms and/or vacancies in the gold layers are considered. In this work, we have tackled these issues by computing the stationary states involved in the thiols adsorption in order to shed light on the kinetics aspects of adsorption process. In this respect, we have considered a variety of thiols into consideration such as methylthiol, dimethylsulfide, dimethyldisulfide, thioacetates, and thiocyanates. We have also considered the cleavage mechanism in the clean and the reconstructed surface scenario and the structure, energetics and spin densities have been computed using electronic structure calculations. For all the studied cases, an homolytic cleavage of CH 3 S-X (X = H, CH 3 , SCH 3 , CN, and COCH 3 ) bond has been found to occur upon adsorption on the gold surface.

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“…All DFT calculations used the Amsterdam Density Functional (ADF) 2010.01 program (41,42). A slab of gold having the bulk structure was passivated in four sites on the (111) surface with either methylamine or ethylthiolate (43,44). C and H atom positions were initially relaxed using the UFF as implemented in the Avogadro 1.1.0 software (45).…”

mentioning

confidence: 99%

Identification of parameters through which surface chemistry determines the lifetimes of hot electrons in small Au nanoparticles

Aruda

Tagliazucchi

Sweeney

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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This paper describes measurements of the dynamics of hot electron cooling in photoexcited gold nanoparticles (Au NPs) with diameters of ∼3.5 nm, and passivated with either a hexadecylamine or hexadecanethiolate adlayer, using ultrafast transient absorption spectroscopy. Fits of these dynamics with temperature-dependent Mie theory reveal that both the electronic heat capacity and the electron-phonon coupling constant are larger for the thiolated NPs than for the aminated NPs, by 40% and 30%, respectively. Density functional theory calculations on ligand-functionalized Au slabs show that the increase in these quantities is due to an increased electronic density of states near the Fermi level upon ligand exchange from amines to thiolates. The lifetime of hot electrons, which have thermalized from the initial plasmon excitation, increases with increasing electronic heat capacity, but decreases with increasing electronphonon coupling, so the effects of changing surface chemistry on these two quantities partially cancel to yield a hot electron lifetime of thiolated NPs that is only 20% longer than that of aminated NPs. This analysis also reveals that incorporation of a temperaturedependent electron-phonon coupling constant is necessary to adequately fit the dynamics of electron cooling. two-temperature model | dissipation T his paper describes an observed dependence of two physical properties-the electronic heat capacity and the electronphonon coupling magnitude-of small (diameter of ∼3.5 nm), completely absorptive plasmonic gold nanoparticles (Au NPs) on the surface chemistry of the NPs. The electronic heat capacity, quantified by the coefficient γ, is the amount of energy required to change the temperature of a population of electrons in the NP. The magnitude of the electron-phonon coupling, quantified by the coefficient g, is a measure of the rate of exchange of energy between the electrons and the lattice. Upon photoexcitation of the Au NPs at the absorption maximum of their plasmon resonance, the plasmonic electron oscillation in the NPs rapidly decoheres to form a thermally equilibrated population of hot electrons (1-8). Within the commonly used "two-temperature model (2TM)," the rate of subsequent cooling of these electrons is dictated by the initial electronic temperature of the particle and the efficiency of dissipation of electronic energy into available vibrational modes. These properties, in turn, depend on the electronic heat capacity of the system and the magnitude of electron-phonon coupling. Our observed dependence of the coefficients γ and g on the chemical structure of the organic adlayer therefore implies that electronic states that participate in the electron cooling process are not only those of the gold lattice, but also orbitals at the metal-organic interface-that is, the surface chemistry of the NPs influences the rate of hot electron cooling.Interest in using metal and semiconductor NPs as optical and/or electronic components within energy conversion systems (9, 10) has inspired studies of ene...

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c(4 × 2) Structures of Alkanethiol Monolayers on Au (111) Compatible with the Constraint of Dense Packing

Cited by 35 publications

References 51 publications

Photoemission core-level shifts reveal the thiolate-Au(111) interface

Photoemission core-level shifts reveal the thiolate-Au(111) interface

On the kinetics and thermodynamics of S–X (X = H, CH3, SCH3, COCH3, and CN) cleavage in the formation of self-assembled monolayers of alkylthiols on Au(111)

Identification of parameters through which surface chemistry determines the lifetimes of hot electrons in small Au nanoparticles

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