Alloy Clusters: Structural Classes, Mixing, and Phase Changes

Results on structural and dynamical properties of model nickel-aluminum alloy clusters are presented and analyzed. A classification scheme of the structural forms is introduced. New general definitions of the mixing energy and mixing coefficient are formulated, and the role of mixing in defining the relative stability of the structural forms is pointed out. The dynamical features are analyzed over a broad energy range. The peculiarities of the solid-to-liquid-like transition in clusters with different stoichiometric composition are described and correlated with the composition-specific features in the energy spectra of the corresponding structural forms. An analytical model, which allows one to estimate a variety of structural and energy characteristics of two-component clusters directly from the parameters of the potential, is presented. An important merit of the model is that it makes transparent the role of the interactions between like atoms vs. those between unlike atoms in defining these characteristics.

[1]  M. Manninen,et al.  Melting and Octupole Deformation of Na 40 , 1998 .

[2]  K. Raghavan,et al.  Ni clusters: structures and reactivity with D2 , 1989 .

[3]  W. Ekardt.  The super-atom model: link between the metal atom and the infinite metal , 1996 .

[4]  R. Car,et al.  Structural transitions in aluminum clusters , 1990 .

[5]  M. Kappes,et al.  Electronic and geometric structure in silver clusters , 1992 .

[6]  R. Whetten,et al.  Critical sizes in the growth of Au clusters , 1997 .

[7]  P. Ziemann,et al.  Investigation of the stabilities of neutral and ionic lead and lead-antimony clusters under single and multiphoton ionization conditions , 1989 .

[8]  J. Doll,et al.  Theoretical studies of the structure and dynamics of metal/hydrogen systems: Diffusion and path integral Monte Carlo investigations of nickel and palladium clusters , 1996 .

[9]  D. Tománek,et al.  Does hydrogen pre-melt palladium clusters? , 1996 .

[10]  Matthias Brack,et al.  The physics of simple metal clusters: self-consistent jellium model and semiclassical approaches , 1993 .

[11]  E. Carter,et al.  Ab initio molecular dynamics of pseudorotating Li5 , 1997 .

[12]  R. Johnston,et al.  Modeling calcium and strontium clusters with many-body potentials , 1997 .

[13]  Rosato,et al.  Tight-binding potentials for transition metals and alloys. , 1993, Physical review. B, Condensed matter.

[14]  Pearson,et al.  Laplace-transform technique for deriving thermodynamic equations from the classical microcanonical ensemble. , 1985, Physical review. A, General physics.

[15]  Sawada,et al.  Melting and magnetic ordering in transition-metal microclusters. , 1989, Physical review. B, Condensed matter.

[16]  Jellinek,et al.  Fragmentation of atomic clusters: A theoretical study. , 1994, Physical review. A, Atomic, molecular, and optical physics.

[17]  P. A. Marcos,et al.  Structural and dynamical properties of Cu–Au bimetallic clusters , 1996 .

[18]  Rademann,et al.  Size dependence of the gradual transition to metallic properties in isolated mercury clusters. , 1987, Physical review letters.

[19]  Walt A. de Heer,et al.  The physics of simple metal clusters: experimental aspects and simple models , 1993 .

[20]  M. Knickelbein,et al.  Photodissociation spectroscopy of NbnArm complexes , 1993 .

[21]  G. C. Nieman,et al.  Binding of deuterium to icosahedral nickel and cobalt clusters , 1996 .

[22]  M. Kappes,et al.  Optical absorption probes of LixNa4−x (x=1,2): Geometry, substitution isomers, and composition‐dependent electron delocalization , 1992 .

[23]  Cheng,et al.  Surface melting of clusters and implications for bulk matter. , 1992, Physical review. A, Atomic, molecular, and optical physics.

[24]  B. K. Rao,et al.  Physics and chemistry of small clusters , 1987 .

[25]  M. Manninen,et al.  Magic triangular and tetrahedral clusters , 1997 .

[26]  P. Armentrout,et al.  Collision‐induced dissociation of Ni+n (n=2–18) with Xe: Bond energies, geometrical structures, and dissociation pathways , 1992 .

[27]  M. Jarrold,et al.  Photodissociation of metal cluster ions. Dissociation energies and optical spectroscopy , 1990 .

[28]  Raju P. Gupta.  Lattice relaxation at a metal surface , 1981 .

[29]  M. Gordon,et al.  An analytical representation of the lowest potential energy surface for the reaction O(3P)+HCl(X 1Σ+) → OH(X 2Π)+Cl(2P) , 1991 .

[30]  I. Z. Fisher,et al.  Statistical theory of liquids , 1964 .

[31]  M. Menon,et al.  Tight-binding molecular-dynamics study of ferromagnetic clusters , 1998 .

[32]  Andreoni,et al.  Melting of small gold particles: Mechanism and size effects. , 1991, Physical review letters.

[33]  O. Novaro,et al.  Nonadditive interactions and the relative stability of neutral and anionic silver clusters , 1995 .

[34]  Thomas L. Beck,et al.  Solid–liquid phase changes in simulated isoenergetic Ar13 , 1986 .

[35]  D. Wales,et al.  Structure and dynamics of model metal clusters , 1993 .

[36]  Rey,et al.  Computer simulation of the ground-state atomic configurations of Ni-Al clusters using the embedded-atom model. , 1996, Physical review. B, Condensed matter.

[37]  N. Rösch,et al.  On the evolution of cluster to bulk properties: a theoretical LCGTO-LDF study of free and coordinated Nin clusters (n=6-147) , 1994 .

[38]  S. Nayak,et al.  Structure and properties of Ni7 cluster isomers , 1996 .

[39]  T. P. Martin,et al.  Shell Structure of Clusters , 1991 .

[40]  J. Jellinek,et al.  Theoretical Dynamical Studies of Metal Clusters and Cluster-Ligand Systems , 1996 .

[41]  W. C. Swope,et al.  A computer simulation method for the calculation of equilibrium constants for the formation of physi , 1981 .

[42]  A. Rosén,et al.  Reactivity of Fe n , Co n , and Cu n Clusters with O 2 and D 2 Studied at Single-Collision Conditions , 1996 .

[43]  G. López,et al.  A Study of Low Temperature Heat Capacity Anomalies in Bimetallic Alloy Clusters using J-Walking Monte Carlo Methods , 1993 .

[44]  Alonso,et al.  Molecular-dynamics study of the structures, binding energies, and melting of clusters of fcc transition and noble metals using the Voter and Chen version of the embedded-atom model. , 1994, Physical review. B, Condensed matter.

[45]  W. Andreoni,et al.  Structural and electronic properties of sodium microclusters (n=2–20) at low and high temperatures: New insights from ab initio molecular dynamics studies , 1991 .

[46]  David M. Rayner,et al.  OPTICAL ABSORPTION SPECTRA OF AU7, AU9, AU11, AND AU13, AND THEIR CATIONS : GOLD CLUSTERS WITH 6, 7, 8, 9, 10, 11, 12, AND 13 S-ELECTRONS , 1994 .

[47]  R. Levine,et al.  Mode Selective Chemistry , 1991 .

[48]  Mark P. Andrews,et al.  Gas-phase "molecular alloys" of bulk immiscible elements: iron-silver (FexAgy) , 1992 .

[49]  B. K. Rao,et al.  Physics and Chemistry of Finite Systems: From Clusters to Crystals , 1992 .

[50]  M. Duncan,et al.  Photodissociation of mass-selected Bi/Cr and Bi/Fe bimetallic clusters , 1990 .

[51]  AB INITIO MONTE CARLO : APPLICATION TO LI8 , 1998 .

[52]  D. Salahub,et al.  Metal-ligand interactions : structure and reactivity , 1996 .

[53]  Hellmut Haberland,et al.  Clusters of Atoms and Molecules II , 1994 .

[54]  Zhang,et al.  Electronic shell structure of simple metal heteroclusters. , 1987, Physical review. B, Condensed matter.

[55]  J. Pittner,et al.  Theoretical exploration of femtosecond multi-state nuclear dynamics of small clusters , 1998 .

[56]  S. Nayak,et al.  ANOMALOUS MAGNETISM IN SMALL MN CLUSTERS , 1998 .

[57]  R. O. Jones,et al.  Density functional study of structure and bonding in lithium clusters Lin and their oxides LinO , 1997 .

[58]  G. Pacchioni,et al.  Elemental and Molecular Clusters , 1988 .

[59]  K. Meiwes-Broer,et al.  Bound-free collective electron excitations in negatively charged silver clusters , 1996 .

[60]  S. Anderson,et al.  CHEMISTRY OF METAL AND SEMIMETAL CLUSTER IONS , 1992 .

[61]  Lai‐Sheng Wang,et al.  Photoelectron spectroscopy of size‐selected transition metal clusters: Fe−n, n=3–24 , 1995 .

[62]  William H. Press,et al.  Numerical recipes , 1990 .

[63]  Š. Vajda,et al.  Observation of Predissociated Excited States in Mixed Alkali Trimer Clusters Na2K and K2Na: Time-Resolved Spectroscopy of Bound−Free Transitions , 1998 .

[64]  R. Smalley,et al.  Ultraviolet photoelectron spectroscopy of copper clusters , 1988 .

[65]  Quantum chemistry of small clusters of elements of groups Ia, Ib, and IIa: fundamental concepts, predictions, and interpretation of experiments , 1991 .

[66]  Julius Jellinek,et al.  NinAlm alloy clusters: analysis of structural forms and their energy ordering , 1996 .

[67]  Landman,et al.  Electronic shell effects in triaxially deformed metal clusters: A systematic interpretation of experimental observations. , 1995, Physical review. B, Condensed matter.