ILM, CNRS UMR 5306 and Université Lyon 1, 43 Bd du 11 Novembre 1918, F69622 Villeurbanne Cedex, France.
J Chem Phys. 2013 Sep 21;139(11):111102. doi: 10.1063/1.4821582.
The energy landscape and kinetics of medium-sized Ag-Au and Ag-Ni nanoalloy particles are explored via a discrete path sampling approach, focusing on rearrangements connecting regions differing in chemical order. The highly miscible Ag27Au28 supports a large number of nearly degenerate icosahedral homotops. The transformation from reverse core-shell to core-shell involves large displacements away from the icosahedron through elementary steps corresponding to surface diffusion and vacancy formation. The immiscible Ag42Ni13 naturally forms an asymmetric core-shell structure, and about 10 eV is required to extrude the nickel core to the surface. The corresponding transformation occurs via a long and smooth sequence of surface displacements. For both systems the rearrangement kinetics exhibit Arrhenius behavior. These results are discussed in the light of experimental observations.
通过离散路径采样方法探索了中等大小的 Ag-Au 和 Ag-Ni 纳米合金颗粒的能量景观和动力学，重点研究了连接化学有序度不同区域的重排。高混溶性的 Ag27Au28 支持大量几乎简并的二十面体同胚。从反核壳到核壳的转变涉及通过对应于表面扩散和空位形成的基本步骤远离二十面体的大位移。不混溶的 Ag42Ni13 自然形成非对称的核壳结构，并且需要大约 10 eV 的能量将镍核挤出到表面。相应的转变通过表面位移的长而平滑的序列发生。对于这两个系统，重排动力学都表现出 Arrhenius 行为。这些结果根据实验观察进行了讨论。
