The structure, energetics and melting behavior of free platinum clusters

Download

index.pdf

Date

2004

Author

Sebetci, Ali

Metadata

Show full item record

Item Usage Stats

174
views

100
downloads

The Voter and Chen version of an embedded-atom model, derived by fitting to experimental data of both the diatomic molecule and bulk platinum simultaneously, has been applied to study the locally stable structures, energetics, growth patterns and melting behavior of free platinum clusters in the size range of N=2-56 and N=75. Using the constant-energy molecular dynamics simulations, thermal and conjugate-gradient minimization techniques, the global minima and the other locally stable structures have been distinguished from those stationary structures that correspond to saddle points of the potential energy surface. The number of isomers and the probabilities of sampling different basins of attractions of the clusters from 2 to 22 atoms are obtained. The energy spectra of these clusters have been analyzed. The correlations between the total energy of the 75-atom cluster and the isomer number and the energy-spectrum-width of the isomers are investigated. The number of isomers of 75-atom cluster as a function of the total energy is presented, and the isomer probability distribution is discussed. The melting behavior of Pt_N clusters in the size range of N=12-14, 54-56, and N=75 has been studied. An atom-resolved analysis method including physical quantities such as the root-mean-square bond-length fluctuations and the coordination numbers for indivudual atoms as the functions of the temperature has been presented. Comparisons have been made with the results of previous calculations using electronic structure and empirical potential methods. The results show that the global minima have structures based on either octahedral, decahedral or icosahedral packing.

Subject Keywords

Metal clusters., Molecular dynamics., Fusion., Phase transformations (Statistical physics)

URI

http://etd.lib.metu.edu.tr/upload/1209980/index.pdf
https://hdl.handle.net/11511/13949

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Thermodynamics of small platinum clusters Sebetci, A; Guvenc, ZB; Kökten, Hatice (Elsevier BV, 2006-03-01) Using the Voter and Chen version of an embedded atom model, derived by fitting simultaneously to experimental data of both the diatomic molecule and bulk platinum, we have studied the melting behavior of free, small platinum clusters in the size range of N = 15-19 in the molecular dynamics simulation technique. We present an atom-resolved analysis method that includes physical quantities such as the root-mean-square bond-length fluctuation and coordination number for individual atoms as functions of tempera...
Energetics and structures of small clusters: Pt(N), N=2-21 Sebetci, A; Guvenc, ZB (Elsevier BV, 2003-02-10) The Voter and Chen version of an embedded-atom model, derived by fitting to experimental data of both diatomic molecule and bulk platinum simultaneously, has been applied to study the locally stable structures, energies and growth patterns of small platinum clusters in the size range of N = 2-21. Using molecular dynamics and thermal quenching simulations, the global minima and the other locally stable structures have been distinguished from those stationary structures that correspond to saddle points of the...
A computer simulation of amorphous silicon Dereli, Guelay; Yalabık, M.Cemal; Ellialtıoğlu, Şinasi (IOP Publishing, 1989-7-1) n this work we simulated the growth of amorphous silicon on a substrate of a two-layer-slab of crystalline silicon with various surface indices. We used the Lennard-Jones form for the pair potentials and the Axilrod-Teller form for the three-body potentials. The growth is realized by means of a continuum Monte-Carlo method and the radial distribution functions are compared for various cases
Numerical simulation of scour at the rear side of a coastal revetment Şentürk, Barış Ufuk; Guler, Hasan Gokhan; Baykal, Cüneyt (2023-05-01) This paper presents the results of a numerical modeling study on the scouring of unprotected rear side material of a rubble mound coastal revetment due to the overtopping of solitary-like waves utilizing a coupled hydro-morphodynamic computational fluid dynamics (CFD) model. Three cases having various wave heights are tested with six different turbulence models together with different wall functions. The hydrodynamic results (free-surface elevations, overtopping volumes, and jet thicknesses) and morphologic...
Stability of gold clusters: molecular-dynamics simulations Erkoç, Şakir (2000-09-01) Structural stability and energetics of gold clusters, Au, (n = 3-555), have been investigated by molecular-dynamics simulations. An empirical model potential energy function has been used in the simulations. Stable structures of the microclusters for n = 3-13 have been determined by molecular-dynamics simulation. It has been found that gold microclusters prefer to form three-dimensional compact structures. Molecular-dynamics simulations have also been performed for spherical gold clusters generated from FCC...

Citation Formats

A. Sebetci, “The structure, energetics and melting behavior of free platinum clusters,” Ph.D. - Doctoral Program, Middle East Technical University, 2004.