This study explores the structural and thermal behavior of 38-atom Pd-Au-Ir nanoalloys with truncated octahedral geometry using a multiscale simulation framework. Gupta many-body potentials were used to determine energetically favorable chemical configurations, which were subsequently refined through density functional theory (DFT) calculations. Among the evaluated compositions, Pd 8 AuFormula: see textIr 6 was identified as the most stable based on mixing energies and energy difference metrics. Local atomic pressure analysis revealed composition-dependent stress distributions, with Pd atoms preferentially occupying hexagonal center (HexC) and (100) corner surface sites. Thermal stability and melting transitions were assessed via molecular dynamics simulations and Lindemann index analysis. A sharp rise in the Lindemann index accompanied by curvature changes in caloric curves indicated the onset of melting. For several compositions, small Formula: see text increases below the melting threshold were correlated with localized coordination shifts from FCC to HCP and BCC environments. Despite these fluctuations, the six-atom Ir core retained its FCC-like structure until melting. These findings underscore the role of chemical ordering and site-specific occupation in governing both the mechanical stress landscape and the thermodynamic stability of Pd-Au-Ir nanoalloys, offering design principles for robust multimetallic nanoclusters.
Garip et al. (Fri,) studied this question.