Searcharxiv⌕ Search

arXiv subjects

Ziya B. Guvenc

Publications and source records attributed to Ziya B. Guvenc.

3 recordsLinked to original sources

Molecular Dynamics Study of a Thermal Expansion Coefficient: Ti Bulk with an Elastic Minimum Image Method

Linear thermal expansion coefficient (TEC) and specific heat of Ti bulk is investigated by means of molecular dynamics simulation. Elastic Minimum Image Convention of periodic boundary conditions is introduced to allow the bulk to adjust its size according to the new temporarily fixed temperature. The TEC and the specific heat of Ti are compared to the available theoretical and experimental data.

physics.comp-ph↗

Global minima of Al_N, Au_N and Pt_N, N=2-80, clusters described by Voter-Chen version of embedded-atom potentials

Using the basin-hopping Monte Carlo minimization approach we report the global minima for aluminium, gold and platinum metal clusters modelled by the Voter-Chen version of the embedded-atom model potential containing up to 80 atoms. The virtue of the Voter-Chen potentials is that they are derived by fitting to experimental data of both diatomic molecules and bulk metals simultaneously. Therefore, it may be more appropriate for a wide range of the size of the clusters. This is important since almost all properties of the small clusters are size dependent. The results show that the global minima of the Al, Au and Pt clusters have structures based on either octahedral, decahedral, icosahedral or a mixture of decahedral and icosahedral packing. The 54-atom icosahedron without a central atom is found to be more stable than the 55-atom complete icosahedron for all of the elements considered in this work. The most of the Al global minima are identified as some fcc structures and many of the Au global minima are found to be some low symmetric structures, which are both in agreement with the previous experimental studies.

physics.atm-clus↗

Molecular Dynamics Simulation of the Melting Behaviours of 12-, 13-, 14-Atom Icosahedral Platinum Clusters

Using molecular dynamics simulation technique, we have studied the melting behaviours of free, icosahedral PtN clusters in the size range of N=12-14. 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 employed in the study. 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 temperature. The results show that while 13-atom icosahedron and 12-atom cluster with a vacancy on the icosahedral surface exhibit one-stage melting, 14-atom cluster with an adatom on the icosahedral surface undergoes two-stage melting, as the temperature increases.

physics.atm-clus↗