Three-body effects in triplets of capped gold nanocrystals

Bauer, Gernot; Gribova, N. V.; Lange, Alexander; Holm, Christian; Groß, Joachim

doi:10.1080/00268976.2016.1213909

Cited by 16 publications

(20 citation statements)

References 31 publications

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“…A substantial number of molecular dynamics simulation studies of the ligand structure of isolated NPs and of the interactions between NPs that utilize these models have been reported . The more sophisticated of these investigations involve simulations that use full atom [10][11][12][13][14][15][16][17][18] and pseudo-atom force fields [19][20][21][22][23][24][25][26][27][28][29], amongst which are a few investigations of the importance of the three NP interaction level deviation from additivity of the pair potential of mean force [23,24,[38][39][40]. The results obtained from these simulations establish that the interaction between the ligands of the dressed nanoparticles, not the core-core interaction, determines the NP monolayer mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

“…(5) We provide an estimate of the many NP induced deviation from additivity of the pair potential of mean force that arises from three-and four-particle proximity to a pair of NPs. Our estimate uses a different representation of the non-additivity than is commonly reported [40]. Rather than explicitly calculating the incremental third NP and fourth NP contributions to the effective force between a pair of NPs, we exploit the very limited range of the pair potential of mean force to define an effective pair potential of mean force and its variation with NP-NP separation.…”

Section: Introductionmentioning

confidence: 99%

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Pair and many-body interactions between ligated Au nanoparticles

Liepold

Smith

Lin

et al. 2019

The Journal of Chemical Physics

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We report the results of molecular dynamics simulations of the properties of a pseudo-atom model of dodecane thiol ligated 5-nm diameter gold nanoparticles (AuNP) in vacuum as a function of ligand coverage and particle separation in three state of aggregation, namely the isolated AuNP, isolated pair of AuNPs and a square assembly of AuNPs. Our calculations show that the ligand density along a radius emanating from the core of an isolated AuNP has the same gross features for all values of the coverage; it oscillates around a constant value up to a distance along the chain corresponding to the position of the fourth pseudo-atom, then smoothly decays to zero, reflecting both the restricted conformations of the chain near the core surface and the larger numbers of conformations available further from the core. Interaction between two AuNPs generates changes in the ligand distributions of each. We examine the structure and general shape of the ligand envelope as a function of the coverage and demonstrate that the equilibrium structure of the envelope and the deformation of that envelope generated by interaction between the NPs is coverage-dependent, so that the shape, depth and position of the minimum of the potential of mean force displays a systematic dependence on the ligand coverage.We propose an accurate analytical description of the calculated potential of mean force as a function of a set of parameters that scale linearly with the ligand coverage. Noting that the conformational freedom of the ligands implies that multiparticle induced deviations from additivity of the pair potential of mean force are likely important, we define and calculate an effective pair potential of mean force for a square configuration of particles; our definition contains, implicitly, both the three-and four-particle contributions to deviation from additivity. We find that the effective pair potential of mean force in this configuration has a different minimum and a different well depth than the isolated pair potential of mean force. Previous work has found that the three-particle contribution to deviation from additivity is

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Pair and many-body interactions between ligated Au nanoparticles

Liepold

Smith

Lin

et al. 2019

The Journal of Chemical Physics

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“…It needs to be examined, however, if for more extreme dimensions (e.g., very long ligands) and for other core and/or cap materials our methodology leads to comparably good results. After two-body interaction, three-body interaction must be studied [4].…”

Section: Discussionmentioning

confidence: 99%

Different ways of looking at the force between two nanocrystals

Lange

Danecker

Bauer

et al. 2015

The Journal of Chemical Physics

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The potential of mean force (PMF) between two nanocrystals (NCs) represents an effective interaction potential that is essential when explaining the assembly of NCs to superstructures. For a given temperature, the PMF is obtained best from molecular dynamics simulations. Based on a density functional approach, this study proposes three methods of predicting the PMF for any given temperature based on a single molecular dynamics simulation for one temperature. The three methods construct the PMF by considering the ligands as an ideal gas, as hard-sphere chains, or as Lennard-Jones interaction sites. To apply this methodology, the density of the interaction centers must be extracted from the simulation data. For the ideal gas model, a straightforward sampling procedure with a fixed lattice in space leads to free energies that are too large in order to consistently explain the simulation data for different temperatures. Naive sampling does not account for the small momenta added to the NCs when coupled to a thermostat. A method is proposed that corrects for the unphysical steps during the simulation. The ideal gas contribution computed for the corrected density is significantly smaller than the one obtained from naive sampling and can thus explain the temperature dependence of the PMF correctly. For the hard-sphere chain model, where a weighted density is used, the correction of the particle density is not essential. However, the PMF calculated based on the corrected density confirms our approach. All three models predict PMF curves in very good agreement with simulation results, but they differ in the number of input parameters and the computational effort. Based on the modeling results, we predict the existence of an additional attractive force at small distances of the NCs - a depletion force.

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“…Clearly, each of these characteristics involves one or more among the following actions: (i) choice of the model structure/topology, (ii) choice of the functional forms for the interactions, (iii) optimization of parameterization. (ii) and (iii) are complex tasks which have been addressed using a large number of different methodologies (Bauer et al, 2017; Lin et al, 2018; Brancolini et al, submitted). Particularly effective are usually combinations of bottom up and top-down strategy (Leonarski et al, 2013; Mereghetti et al, 2016) including both atomistic simulations and experimental data (Trovato and Tozzini, 2014) from different sources (e.g., structural, or thermodynamic).…”

Section: The Landscape Of Coarse Grained Np Modelsmentioning

confidence: 99%

“…The problem can be solved by attributing larger masses to the peripheral beads. The proper balance of masses can be found by imposing that the total mass and the total rotational inertia correspond to that of the atomistic NP (Bauer et al, 2017).…”

Section: Rational Building Of a Minimalist Np Modelmentioning

confidence: 99%