Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8651
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Conference Object Citation - WoS: 3Citation - Scopus: 5Reactivity of the Nin(T) (N=54,55,56) Clusters With D2(V,j) Molecule: Molecular Dynamics Simulations(Elsevier Science Bv, 2004) Özçelik, S; Güvenç, ZB; Durmus, P; Jellinek, JThe reactive channel of the D(2) (v, j) + Ni(n) (T) (n = 54, 55, 56) collision system is studied via quasiclassical molecular dynamics simulations. The cluster is described using an embedded-atom potential, and the interaction between the molecule and the cluster is modeled by a LEPS (London-Eyring-Polanyi-Sato) potential energy function. Dissociative chemisorption probabilities are computed as functions of the impact parameter and the collision energy, and are used to evaluate the reaction cross-sections. Effects of the initial rovibrational states of the molecule and the temperatures of the clusters on the reactive channel are analyzed. Reaction rate constants are also computed and compared with those measured experimentally. (C) 2004 Elsevier B.V. All rights reserved.Conference Object Citation - WoS: 14Citation - Scopus: 13Structures and Energetics of Pd21-Pd55 Clusters(Elsevier Science Bv, 2003) Karabacak, M; Özçelik, S; Güvenç, ZBUsing molecular dynamics and thermal quenching simulations the stable geometrical structures and energies of Pd-n (n = 21-55) clusters are identified. The interaction between the cluster atoms is modeled by an embedded-atom (EA) potential energy surface, Voter and Chen's version. The stable geometrical structures and their minimum energies are obtained from 500 phase space coordinates generated along high-energy trajectories. The internal energies (about T = 2500 K) are above the melting temperature of the Pd-n clusters. The thermal quenching technique is employed to remove slowly the internal kinetic energy of the clusters. Because of this slow minimization process the locally stable isomers are separated from those meta-stable ones. Stability of the clusters is examined by the first and the second energy differences. The average bond lengths are obtained and analyzed as a function of the size of the clusters. (C) 2003 Elsevier Science B.V. All rights reserved.Conference Object Citation - WoS: 30Citation - Scopus: 31Structures and Melting of Cun (N=13, 14, 19, 55, 56) Clusters(Elsevier Science Bv, 2003) Özçelik, S; Güvenç, ZBConstant-energy molecular dynamics simulation was utilized to study the most stable geometrical structures, binding energy, melting, phase changes of Cu-n (n = 13, 14, 19, 55, 56) clusters. These sizes form shell and near shell structures. The cohesion of clusters is modeled by an embedded-atom potential, which contains many-body atomic interaction terms. Phase space coordinates which are generated along high-energy trajectories are used as the initial configurations (500 independent configurations) for thermal quenching in order to obtain the most stable isomers. The melting temperatures of the clusters are estimated. The melting-like transition is described in terms of relative root-mean-square bond-length fluctuations, specific heats, and caloric curves. (C) 2003 Elsevier Science B.V. All rights reserved.Conference Object Citation - WoS: 36Citation - Scopus: 30Structures and Energetics of Pdn (n=2-20) Clusters Using an Embedded-Atom Model Potential(Elsevier Science Bv, 2002) Karabacak, M; Özçelik, S; Güvenç, ZBWe have studied the structure and energetics of the stable isomers of Pd(n) (n = 2-20) clusters by using molecular dynamics and slow-quenching techniques. Cohesion of the clusters is modeled by an embedded-atom potential due to Voter and Chen, which contains many-body atomic interactions. The isomers' statistics are obtained from 10000 independent initial configurations, which have been generated along a high-energy trajectory (the chosen energy value is high enough to melt the cluster). The internal kinetic energy of these initial conditions is removed slowly. Because of this slow minimization process the locally stable isomers are separated from those meta-stable ones. Probabilities belonging to sampling the basins of attractions of each isomer are computed, and compared with each other. Furthermore, the spectrum, which is formed by isomers' energies, is analyzed. (C) 2002 Published by Elsevier Science B.V.Article Citation - WoS: 22Citation - Scopus: 21Structure and Reactivity of Nin (n=7-14, 19) Clusters(Wiley, 2001) Böyükata, M; Güvenç, ZB; Özçelik, S; Durmus, P; Jellinek, JResults of a computer simulation study of Ni-n (n = 7-14, 19) clusters, their structures, energetics, and reactivity with a D-2 molecule are presented. The clusters are described by an embedded atom potential, whereas the interaction between the molecule and the clusters is modeled by an LEPS (London-Eyring-Polanyi-Sato) potential energy function. The focus is on structures of the dusters and their reactive channels. The total numbers of stable isomers of the clusters are obtained by sampling their phase space, and the isomers' energy spectra are determined. On the reactive side, dissociative chemisorptions cross sections and decay-rate constants are calculated. (C) 2001 John Wiley & Sons, Inc.Conference Object Citation - WoS: 12Citation - Scopus: 14Reactions of Small Ni Clusters With a Diatomic Molecule: Md Simulation of D2+nin (n=7-10) Systems(Elsevier Science Bv, 2000) Durmus, P; Böyükata, M; Özçelik, S; Güvenç, ZB; Jellinek, JThe kinetics of the reactions of nickel clusters with a deuterium molecule are studied, Dissociative chemisorption probabilities of the D(2) molecule on the small Ni(n) (n=7-10) clusters are computed by a quasi-classical molecular dynamics computer simulation technique. Structures of the clusters are obtained by an embedded-atom potential, and the interaction between the D(2) and Ni(n) is modelled by an LEPS (London-Eyring-Polanyi-Sato) function (energy surface). This analysis includes the chemisorption probabilities as functions of the impact parameter and of the relative translational energy of the D(2). The corresponding reactive cross-sections for the ground state of the molecule are calculated as functions of the collision energy and the size of the cluster. The role of the size of the clusters is examined. An indirect mechanism to the reaction, which involves formation of molecular adsorption as precursors to dissociative adsorption in the low collision energy region (less than 0.1eV), is observed. Results are discussed by comparing with the other similar theoretical and experimental studies. (C) 2000 Elsevier Science B.V. All rights reserved.