Global optimization of bimetallic cluster structures. II. Size-matched Ag-Pd, Ag-Au, and Pd-Pt systems.

Genetic algorithm global optimization of Ag-Pd, Ag-Au, and Pd-Pt clusters is performed. The 34- and 38-atom clusters are optimized for all compositions. The atom-atom interactions are modeled by a semiempirical potential. All three systems are characterized by a small size mismatch and a weak tendency of the larger atoms to segregate at the surface of the smaller ones. As a result, the global minimum structures exhibit a larger mixing than in Ag-Cu and Ag-Ni clusters. Polyicosahedral structures present generally favorable energetic configurations, even though they are less favorable than in the case of the size-mismatched systems. A comparison between all the systems studied here and in the previous paper (on size-mismatched systems) is presented.

[1]  Giulia Rossi,et al.  Global optimization of bimetallic cluster structures. I. Size-mismatched Ag-Cu, Ag-Ni, and Au-Cu systems. , 2005, The Journal of chemical physics.

[2]  Said Salhi,et al.  Theoretical investigation of isomer stability in platinum–palladium nanoalloy clusters , 2004 .

[3]  D. Goodman,et al.  The growth of Ag–Au bimetallic nanoparticles on TiO2(1 1 0) , 2004 .

[4]  L. Stievano,et al.  Structure and catalytic activity of palladium–platinum aggregates obtained by laser vaporisation of bulk alloys , 2001 .

[5]  Z. Bastl,et al.  Bimetallic (Ag)Au nanoparticles prepared by the seed growth method: two-dimensional assembling, characterization by energy dispersive X-ray analysis, X-ray photoelectron spectroscopy, and surface enhanced raman spectroscopy, and proposed mechanism of growth. , 2004, Langmuir : the ACS journal of surfaces and colloids.

[6]  P. Provencio,et al.  Heterogeneous growth of metal clusters from solutions of seed nanoparticles. , 2004, Journal of the American Chemical Society.

[7]  Riccardo Ferrando,et al.  Crossover among structural motifs in transition and noble-metal clusters , 2002 .

[8]  F Baletto,et al.  Magic polyicosahedral core-shell clusters. , 2004, Physical review letters.

[9]  Jaroslav V. Burda,et al.  Density functional study of structural and electronic properties of bimetallic silver–gold clusters: Comparison with pure gold and silver clusters , 2002 .

[10]  Bertolini,et al.  Theory of segregation using the equivalent-medium approximation and bond-strength modifications at surfaces: Application to fcc Pd-X alloys. , 1996, Physical review. B, Condensed matter.

[11]  C. Geantet,et al.  Hydrogenation of Tetralin in the Presence of Sulfur over γ-Al2O3-Supported Pt, Pd, and Pd–Pt Model Catalysts , 2001 .