A Gupta potential for magnesium in hcp phase

2015 ◽  
Vol 98 ◽  
pp. 328-332 ◽  
Author(s):  
Xiaojie Li ◽  
Ying Qin ◽  
Jie Fu ◽  
Jijun Zhao
Keyword(s):  
Author(s):  
Huseyin Yildirim

In this paper, the melting behaviors of Rh–Ag–Au nanoalloys are investigated with MD simulation. For Rh–Ag–Au nanoalloys, icosahedron structure was considered. The local optimizations of Rh–Ag–Au nanoalloys were carried out with the BH algorithm. The interatomic interactions were modeled with the Gupta potential. The local optimization results of Rh–Ag–Au nanoalloys show that Au and Ag atoms prefer to locate on the surface, and Rh atoms prefer to locate in the inner shells. The bond order parameter result is compatible with the excess energy analysis. It is noted that structures with more Ag–Au bonds are more energetically stable. Caloric curve, heat capacity, Lindemann index, and RMSD methods were used for estimating the melting temperatures of Rh–Ag–Au nanoalloys. According to the simulation results, melting temperatures depend on the composition. Also, it is discovered that nanoalloys are generally melting in two stages. Surface melting of the third shell is occupied by Ag and Au atoms, and then homogeneous melting of the inner shells is occupied by Rh atoms. It is found that the difference between surface melting temperatures and homogeneous melting temperatures in Ag-poor compositions is more significant than that of Ag-rich nanoalloys. In addition, the melting temperatures of the nanoalloys are found to be increased as the size of nanoalloys increases.


2005 ◽  
Vol 19 (15n17) ◽  
pp. 2339-2344 ◽  
Author(s):  
EVA M. FERNÁNDEZ ◽  
LUIS C. BALBÁS ◽  
LUIS A. PÉREZ ◽  
KARO MICHAELIAN ◽  
IGNACIO L. GARZÓN

The structural properties and energy ordering of the lowest lying isomers of bimetallic ( CuAu )n and ( PtPd )n, n=5-22 clusters have been investigated by means of density functional theory (DFT) in the generalized gradient approximation (GGA). The initial cluster geometry optimization is performed by using a genetic algorithm with the many body Gupta potential. This technique provide a distribution of the lowest energy cluster structures, that are further reoptimized using the DFT-GGA methodology. The energy ordering of isomers obtained with the Gupta potential does not agree, in general, with the one obtained using DFT-GGA for the two bimetallic clusters investigated. However, the lowest energy strucutures of the ( CuAu )n nanoalloy show icosahedral patterns in agreement with the results obtained with the model potential. For the ( PtPd )n clusters segregation effects are found, where the Pt atoms are forming the cluster core and the Pd atoms are on the cluster surface, in agreement with previous calculations using the many body Gupta potential.


2020 ◽  
Vol 34 (08) ◽  
pp. 2050063
Author(s):  
Ali Kemal Garip ◽  
Songül Taran

Using Monte Carlo Basin-hopping algorithm within the Gupta potential, a systematic investigation has been performed for the best chemical ordering structures of 19-atom trimetallic [Formula: see text] nanoclusters with double icosahedral geometry. The structures with the lowest energy at Gupta level are then re-optimized by DFT relaxations and the DFT relaxations confirmed the lowest energy structures obtained at the Gupta level indicating the double icosahedron structure is favorable for 19-atom [Formula: see text] nanoclusters. It was observed that the caloric curves exhibit a smoother transition with structural isomerizations other than a sharp jump behavior.


2020 ◽  
Vol 754 ◽  
pp. 137635
Author(s):  
W.M. Keyampi ◽  
T.S. Tsasse ◽  
B. Nana ◽  
S. Zekeng

2019 ◽  
Vol 6 (8) ◽  
pp. 190342 ◽  
Author(s):  
Rongbin Du ◽  
Sai Tang ◽  
Xia Wu ◽  
Yiqing Xu ◽  
Run Chen ◽  
...  

The stable structures of Ag–Au and Cu–Au clusters with 1 : 1, 1 : 3 and 3 : 1 compositions with up to 108 atoms are obtained using a modified adaptive immune optimization algorithm with Gupta potential. The dominant motifs of Ag–Au and Cu–Au clusters are decahedron and icosahedron, respectively. However, in Ag-rich Ag–Au clusters, more icosahedra are found, and in Cu-rich Cu–Au clusters, there exist several decahedral motifs. Four Leary tetrahedral motifs are predicted. Cu core Au shell configurations are predicted in Cu–Au clusters. In Ag–Au clusters, most Ag atoms are on the surface, but partial ones are located in the inner shell, while Au atoms are interconnected in the middle shell.


2009 ◽  
Vol 4 ◽  
pp. 65-77 ◽  
Author(s):  
Veena Verma ◽  
Keya Dharamvir

Various gold nanowires with very small cross-sections (few atoms) have been studied using the Gupta potential. Gold nanowire icosa structure is found to be most stable among structures studied. The values of cohesive energy, Young’s modulus and shear modulus have been computed and all the values (except poisson ratio) are more than that of bulk gold. Another striking observation about gold nanostructures is that the Young’s modulus increases with tube radius whereas shear modulus decreases.


2006 ◽  
Vol 20 (09) ◽  
pp. 485-494
Author(s):  
SHI-WEI REN

By using the standard microcanonical molecular-dynamics simulations, the melting behaviors of the clusters bound by Gupta potentials are investigated. The calculations indicate that these clusters can show different melting behaviors. The origins of these processes are studied. The effects of the attractive range and the repulsive part of the interatomic interaction on the melting behaviors of the clusters are compared and analyzed.


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