Changing of the shape and structure of Cu nanoclusters generated from a gas phase: MD simulations

Чепкасов, И. В.; Gafner, Yu. Ya.; Гафнер, С. Л.

doi:10.1016/j.jaerosci.2015.09.004

Cited by 35 publications

(16 citation statements)

References 20 publications

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“…For a more accurate understanding of all the processes, we first provide data on copper condensation since gold atoms were considered as an impurity in this case. In part, we performed the analysis shown in [ 22 ], which shows that under similar conditions of simulation synthesis, at the final stage of the simulation ( T = 77 K), most of the particles obtained had a size of up to 4000 atoms. This value corresponds to the approximate diameter value of the spherical cluster ( D = 4.61 nm).…”

Section: Resultsmentioning

confidence: 99%

The role of gold atom concentration in the formation of Cu–Au nanoparticles from the gas phase

Gafner

Гафнер

Ryzkova

et al. 2021

Beilstein J. Nanotechnol.

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The synthesis of bimetallic nanoparticles need to be controlled in order to obtain particles of a desired size, spatial structure, and chemical composition. In the synthesis of the Cu–Au nanoparticles studied here, nanoparticles can be obtained through either chemical or physical methods, each of which has its own drawbacks. Although it is very difficult to achieve the required target chemical composition of nanoparticles during chemical synthesis, their size can be stabilized quite well. In turn, physical synthesis methods mainly allow to maintain the required chemical composition; however, the size of the resulting particles varies significantly. To solve this issue, we studied the formation of Cu–Au nanoparticles with different chemical compositions from a gaseous medium using computer molecular dynamics (MD) simulation. The aim was to determine the effect of the concentration of gold atoms on the size and on the actual chemical composition of the formed bimetallic nanoparticles. The modeled region had a cubic shape with a face length of 1350 Bohr radii and contained a total of 91125 copper and gold atoms uniformly distributed in space. Thus, based on the results of the MD simulation, it was concluded that an increase in the percentage of gold atoms in the initial vapor phase led to a decrease in the size of the synthesized nanoparticles. In addition, it was found that clusters with a size of more than 400–500 atoms, regardless of the chemical composition of the initial vapor phase, basically corresponded to a given target composition.

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Section: Resultsmentioning

confidence: 99%

The role of gold atom concentration in the formation of Cu–Au nanoparticles from the gas phase

Gafner

Гафнер

Ryzkova

et al. 2021

Beilstein J. Nanotechnol.

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“…Отметим, что потенциал сильной связи (tight-binding) очень хорошо зарекомендовал себя и при моделировании систем конденсации. Так в [13,18,19] авторами также была смоделирована конденсация атомов меди в среде виртуальных частиц. Полученные в [13,18,19] результаты хорошо сходятся с экспериментальными данными по таким основным параметрам системы как вид распределения получаемых частиц по размерам, структурам и формам.…”

Section: описание компьютерной моделиunclassified

Analysis of the size distribution of binary Cu-Au nanoparticles during synthesis from a gaseous medium

2020

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The paper presents the results of molecular dynamics computer simulation studies on the synthesis of binary Cu-Au nanoclusters by condensation from the gaseous phase. To calculate the interatomic interaction forces, the modified TB-SMA potential with a fixed cutoff radius was used. As the initial structure, a configuration containing a total of 91 124 Cu and Au atoms distributed in a cubic lattice with a parameter of 30 • а В , where а В is the Bohr radius, was chosen and periodic boundary conditions were used. For the analysis, we selected the initial configurations of different chemical composition Cu 3 Au, Cu-Au, Cu 90 Au 10 , Cu 60 Au 40 , which were cooled in the condensation process to 77 K. As a result of numerical experiments, condensation of liquid droplets from hot high-density gas was observed, which then crystallized into primary particles of nanometer size and then merged into larger formations. According to the simulation results, a relationship was found between the number of clusters formed at the first stage of synthesis and the percentage of gold atoms in the primary gaseous medium. It was concluded that this fact was a consequence of different binding energies between copper and gold atoms, which led to different melting points of these clusters. Despite the random nature of further agglomeration processes, this trend still persists at lower temperatures. Therefore, using different concentrations of copper and gold atoms, it is possible, in principle, to control the formation of Cu-Au binary clusters from the gas phase with some predetermined chemical composition and size.

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“…This experimental result is consistent with the obvious estimate, since the power of the probe laser is much lower than the power of the electric heater. Most likely, these crystals are formed due to the deposition and subsequent growth of copper particles [5,20,21]. It is interesting that the surface pattern depends considerably on the probe laser radiation.…”

Section: Surface Patterns On Samples Of Solid Copper Samples After Thmentioning

confidence: 99%

Interaction of a Low-Power Laser Radiation with Nanoparticles Formed over the Copper Melt in Rarefied Argon Atmosphere

Dombrovsky

Mendeleyev

2020

Thermo

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Two effects have been recently observed by the authors for the copper sample melted in a rarefied argon atmosphere. The first of these effects is a strong decrease in the normal reflectance of a copper sample with time just after the beginning of melting. A partially regular crystal structure was also formed on the surface of the solid sample after the experiment. Both effects were explained by generation of a cloud of levitating nanoparticles. Additional experiments reported in the present paper show that the rate of decrease in reflectance increases with pressure of argon atmosphere and the surface pattern on the solid sample after the experiment depends on the probe laser radiation. It is theoretically shown for the first time that the dependent scattering effects in the cloud of copper nanoparticles are responsible for the abnormal decrease in normal reflectance and also for the observed significant role of light pressure in deposition of nanoparticles on the sample surface. The predicted minimum of normal reflectance is in good agreement with the experimental value.

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Changing of the shape and structure of Cu nanoclusters generated from a gas phase: MD simulations

Cited by 35 publications

References 20 publications

The role of gold atom concentration in the formation of Cu–Au nanoparticles from the gas phase

The role of gold atom concentration in the formation of Cu–Au nanoparticles from the gas phase

Analysis of the size distribution of binary Cu-Au nanoparticles during synthesis from a gaseous medium

Interaction of a Low-Power Laser Radiation with Nanoparticles Formed over the Copper Melt in Rarefied Argon Atmosphere

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