Open AccessComparative modelling of chemical ordering in palladium-iridium nanoalloys
Author(s) -
Jack B. A. Davis,
Roy L. Johnston,
Leonid Rubinovich,
M. Polak
Publication year - 2014
Publication title -
the journal of chemical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.071
H-Index - 357
eISSN - 1089-7690
pISSN - 0021-9606
DOI - 10.1063/1.4903188
Subject(s) - iridium , palladium , maxima and minima , atom (system on chip) , octahedron , density functional theory , dopant , magic number (chemistry) , cluster (spacecraft) , materials science , computational chemistry , chemistry , crystallography , crystal structure , doping , electronic structure , mathematics , catalysis , organic chemistry , computer science , mathematical analysis , optoelectronics , embedded system , programming language
Chemical ordering in "magic-number" palladium-iridium nanoalloys has been studied by means of density functional theory (DFT) computations, and compared to those obtained by the Free Energy Concentration Expansion Method (FCEM) using derived coordination dependent bond energy variations (CBEV), and by the Birmingham Cluster Genetic Algorithm using the Gupta potential. Several compositions have been studied for 38- and 79-atom particles as well as the site preference for a single Ir dopant atom in the 201-atom truncated octahedron (TO). The 79- and 38-atom nanoalloy homotops predicted for the TO by the FCEM/CBEV are shown to be, respectively, the global minima and competitive low energy minima. Significant reordering of minima predicted by the Gupta potential is seen after reoptimisation at the DFT level.
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