Atomistic Simulations of fcc Pt(75)Ni(25) and Pt(75)Re(25) Cubo-octahedral Nanoparticles.

Wang, G. ; Van Hove, M. A. ; Ross, P. N. ; Baskes, M. I.

Technical Information Center Oak Ridge Tennessee

关键词: Alloys;    Atoms;    Simulation;    Electronic structures;    Monte Carlo method;   

RP-ID  :  DE2004822978

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

We have developed interatomic potentials for Pt-Ni and Pt-Re alloys within the modified embedded atom method (MEAM). Furthermore, we applied these potentials to study the equilibrium structures of Pt75Ni25 and Pt75Re25 nanoparticles at T=600 K using the Monte Carlo method. In this work, the nanoparticles are assumed to have disordered fcc cubo-octahedral shapes (terminated by (111) and (100) facets) and contain from 586 to 4033 atoms (corresponding to a diameter from 2.5 to 5 nm). It was found that, due to surface segregation, (1) the Pt75Ni25 nanoparticles form a surface-sandwich structure: the Pt atoms are enriched in the outermost and third atomic shells, while the Ni atoms are enriched in the second atomic shell; (2) the equilibrium Pt75Re25 nanoparticles adopt a core-shell structure: a Pt-enriched shell surrounding a Pt-deficient core.