Thermal Properties of Co/Au Nanoalloys and Comparison of Different Computer Simulation Techniques

Rapallo, Arnaldo; Olmos-Asar, Jimena A.; Oviedo, Oscar Alejandro; Ludueña, Martín; Ferrando, Riccardo; Mariscal, Marcelo M.

doi:10.1021/jp302001c

Cited by 51 publications

(32 citation statements)

References 47 publications

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“…The thermal stability and surface alloying of M-Au NCs have been investigated by theoretical simulations techniques. 30 However, those studies have only focused on NCs with fewer atoms, in many cases much smaller than the general experimentally prepared NCs. On the other hand, the thermal stability and the segregation process of a large lattice mismatch, immiscible M-Au NCs system consisting of different structures and composition have seldom been studied so far.…”

Section: Introductionmentioning

confidence: 99%

Tailoring characteristic thermal stability of Ni-Au binary nanocrystals via structure and composition engineering: theoretical insights into structural evolution and atomic inter-diffusion

Xing

Wang

et al. 2014

AIP Advances

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We report on the structural evolution and atomic inter-diffusion characteristics of the bimetallic Ni-Au nanocrystals (NCs) by molecular dynamics simulations studies. Our results reveal that the thermal stability dynamics of Ni-Au NCs strongly depends on the atomic configurations. By engineering the structural construction with Ni:Au = 1:1 atomic composition, compared with core-shell Au@Ni and alloy NCs, the melting point of core-shell Ni@Au NCs is significantly enhanced up to 1215 K. Unexpectedly, with atomic ratio of Au:Ni= 1:9, the melting process initiates from the atoms in the shell of Ni@Au and alloy NCs, while starts from the core of Au@Ni NCs. The corresponding features and evolution process of structural motifs, mixing and segregation are illustrated via a series of dynamic simulations videos. Moreover, our results revealed that the face centered cubic phase Au0.75Ni0.25 favorably stabilizes in NCs form but does not exist in the bulk counterpart, which elucidates the anomalies of previously reported experimental results on such bimetallic NCs.

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Section: Introductionmentioning

confidence: 99%

Tailoring characteristic thermal stability of Ni-Au binary nanocrystals via structure and composition engineering: theoretical insights into structural evolution and atomic inter-diffusion

Xing

Wang

et al. 2014

AIP Advances

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“…The problem of NPs coalescence is a hot research area [36][37][38][39][40][41][42][43][44] as well as the study of bimetalic NPs and their remarkable features. [45][46][47][48][49][50] For the coalescence process presented here, the simulation results can be directly compared with those obtained from straightforward MD simulations performed in our previous work. 31 In the case of P b (y), a better agreement is found for energies below E. This can be understood considering that this portion of P b (y) is predicted using the gaussian approximation of P (x) (equation 14) at energies closer to X , where the approximation is better.…”

Section: Testing the Methods For The Coalescence Of Nanoparticlesmentioning

confidence: 99%

Time Recovery for a Complex Process Using Accelerated Dynamics

Paz

Leiva

2015

J. Chem. Theory Comput.

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The hyperdynamics method (HD) developed by Voter (J. Chem. Phys. 1996, 106, 4665) sets the theoretical basis to construct an accelerated simulation scheme that holds the time scale information. Since HD is based on transition state theory, pseudoequilibrium conditions (PEC) must be satisfied before any system in a trapped state may be accelerated. As the system evolves, many trapped states may appear, and the PEC must be assumed in each one to accelerate the escape. However, since the system evolution is a priori unknown, the PEC cannot be permanently assumed to be true. Furthermore, the different parameters of the bias function used may need drastic recalibration during this evolution. To overcome these problems, we present a general scheme to switch between HD and conventional molecular dynamics (MD) in an automatic fashion during the simulation. To decide when HD should start and finish, criteria based on the energetic properties of the system are introduced. On the other hand, a very simple bias function is proposed, leading to a straightforward on-the-fly set up of the required parameters. A way to measure the quality of the simulation is suggested. The efficiency of the present hybrid HD-MD method is tested for a two-dimensional model potential and for the coalescence process of two nanoparticles. In spite of the important complexity of the latter system (165 degrees of freedoms), some relevant mechanistic properties were recovered within the present method.

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“…Nanoalaşımların termal kararlılığının, topak boyutu, kompozisyon ve yapısal özelliklere bağlı olması sebebiyle deneysel yöntemlerle araştırılması zordur. Teorik yöntemlerde son gelişmeler teorik simülasyonların ve hesaplamaların nanoalaşımların yapısal ve termal özellikleri hakkında bilgi sağladığını göstermektedir [25][26][27][28][29][30][31]. Örneğin, bir oksijen molekülünün poliikosahedral Ag32Cu6 üzerine adsorpsiyonu, oksijen indirgeme reaksiyonlarındaki O2 ayrışma katalitik özelliklerinin tanımlanması açısından önem taşımaktadır [32].…”

Section: Introductionunclassified

Kesilmiş Oktahedron Yapısına Sahip PdnPt(6-n)Au32 Nanoalaşımlarının Erime Dinamiği

Garip

2020

Düzce Üniversitesi Bilim Ve Teknoloji Dergisi

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Bu çalışmada, kesilmiş oktahedron yapısına sahip PdnPt(6-n)Au32 nanoalaşımlarının kanonik topluluk koşullarındaki (NVT) klasik Moleküler Dinamik simülasyonları, erime dinamiğini incelemek için iki farklı ısıtma oranı ile gerçekleştirilmiştir. MD simülasyonlarında kullanılacak başlangıç konfigürasyonlarını elde edebilmek için topağın kimyasal düzeni, kesilmiş oktahedron yapısında değişimlere izin vermeyecek şekilde Basin-Hopping algoritması ile optimize edilmiştir. Atomlar arası etkileşimleri modellemek için Gupta çok-cisim potansiyeli kullanılmıştır. Elde edilen kalorik eğriler ve erime geçişini incelemek için kullanılan Lindemann indeksi değişim grafikleri göstermektedir ki erime geçişi belirli bir sıcaklık aralığında ve bir izomerizasyon şeklinde gerçekleşmektedir. Keskin olmayan kalorik eğri geçişleri camsı benzeri geçiş olarak sınıflandırılmıştır. İzomerizasyonun gerçekleştiği sıcaklık aralığı ise ısıtma oranı değerine bağlı olarak değişmektedir.

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Thermal Properties of Co/Au Nanoalloys and Comparison of Different Computer Simulation Techniques

Cited by 51 publications

References 47 publications

Tailoring characteristic thermal stability of Ni-Au binary nanocrystals via structure and composition engineering: theoretical insights into structural evolution and atomic inter-diffusion

Tailoring characteristic thermal stability of Ni-Au binary nanocrystals via structure and composition engineering: theoretical insights into structural evolution and atomic inter-diffusion

Time Recovery for a Complex Process Using Accelerated Dynamics

Kesilmiş Oktahedron Yapısına Sahip PdnPt(6-n)Au32 Nanoalaşımlarının Erime Dinamiği

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