Comparative molecular dynamics study of melting and crystallization of Ni and Au nanoclusters

On the size dependence of the surface energy of metal nanoclusters

“…At the same time, the distances between the closest neighbors corresponding to radius r 1 of the first coordination sphere in clusters with the IS and fcc structure are almost equal, because these particles are densely packed. Radii (i ≥ 2) of other coordination spheres for particles with an IS and fcc structure are also very close to each other, as follows, in particular, from our molecular dynamics calcula tions [27][28][29][30] performed with the use of the TBP. In addition, these results show that, up to melting tem perature, the presence of atoms over solid metal parti cles may be ignored.…”

“…∞ u values that we have calculated for potential in the center of a nanocluster containing five atomic shells (see Table 1), and the average values of cohesive energy per atom that we have previously found with the use of the TBP and molecular dynamics simulation [27,29,30]. However, according to formula (13), specific sur face energy is determined by the difference between two close values of cohesive energy, i.e., nanocluster energy U and energy of the same num ber of atoms in the reference bulk phase.…”

“…Since it is difficult to derive an analytical expression for potential that would be valid at an arbitrary value of radial coordinate r we, in this work, directly calculate the value of relevant to the particle center, and the value for an external mono layer. The results of our molecular dynamics studies [27][28][29][30] have shown that, for metal nanoclusters in the solid state even at temperatures close to the melting point, the identification of an external atomic mono layer does not encounter any difficulties. Further more, the function may be approximated using the linear interpolation of and values.…”

“…This potential was tested in [26] when calculating the thermodynamic and elastic char acteristics of Al and Pb bulk metal phases. We have successfully used it previously [27][28][29][30] for determin ing the thermodynamic and structural characteristics of metal nanoclusters.…”

On the effect of heating and cooling rates on the melting and crystallization of metal nanoclusters

“…The authors of [3] also observed the melting and crystallization hysteresis for values of R i ≈ 2 nm. In view of poor experimental data on melting and crystallization hysteresis in nanoparticles, our group was engaged for the last five years in molecular-dynamic simulation of this phenomenon [4][5][6][7][8][9]; the group headed by Gafner performed independent computer experiments using a different software, but the same many-particle potential, viz., the tight binding potential [10]. Both series of computer experiments completely confirmed the existence of the melting and crystallization hysteresis for nanoparticles.…”