Structures and Energetics of Cu21-Cu71 Clusters:A Molecular Dynamics Study

Yıl 2009, Cilt: 22 Sayı: 1, 15 - 19, 22.03.2010

Saime Çetin Süleyman Özçelik , Ziya B. Güvenç

Öz

Using Molecular Dynamics and thermal quenching simulations the stable geometrical structures and energies of Cun (n=21-71) clusters are identified. The interaction between the cluster atoms is modeled by an Embedded-Atom Potential Surface, Voter and Chen’s version. The stable geometrical structures and energies are obtained from 500 phase space coordinates generated along high-energy trajectories. The internal energy (about T=2500 K) is above the melting temperature of the Cun 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.

 

Key Words: Cu clusters, Cluster Structures, Molecular Dynamics, Computer Simulations.

 

Anahtar Kelimeler

-

A Molecular Dynamics Study

Öz

Kaynakça

• Calaminici, P., Koster, A.M., Russo, N., Salahub, D.R., “A density functional study of small copper clusters: Cun (n≤5)”, J. Chem. Phys., 105 (21): 9546-9556 (1996).
• Jug, K., Zimmermann, B., Calaminici, P., Köster, A.M., “Structure and stability of small copper clusters”, J. Chem. Phys., 116: 4497-4507 (2002).
• Karabacak, M., Özçelik, S., Güvenç, Z.B., “Structures and energetics of Pdn, (n= 2-20) clusters using an embedded-atom model potential”, Surf. Sci., 507: 636-642, (2002); and references there in.
• Böyükata, M., Güvenç, Z.B., Özçelik, S., Durmuş, P., Jellinek, J., “Structure and Reactivity of Nin (n=7-14, 19) Clusters”, Int. J. Quant. Chem., 84: 208-215 (2001).
• Benedek, G., Pacchioni, M., ''Elemental and Molecular Clusters’’, Springer- Verlag, Berlin, 20-32, (1998).
• Bernstein, E.R., ‘‘Atomic and Molecular Clusters’’, Springer-Amsterdam, 43-51 (1990).
• Jellinek, J., Güvenç, Z.B., ‘‘Physics and Chemistry of Finite Systems: From Clusters to Crystals’’, Jena, P., Khanna, S.N. and Rao, B.K, eds, Kluwer Academic Publishers, Dordrecht, Vol.II, 1047- 1056 (1992).
• Güvenç, Z.B., Jellinek, J., Voter, A.F., ‘‘Physics and Chemistry of Finite Systems: From Clusters to Crystals’’, Jena, P., Khanna, S.N., and Rao, B.K, eds., Kluwer Academic Publishers, Dordrecht, I: 411-416 (1992).
• Güvenç, Z.B., Jellinek, J., “Surface Melting in Ni55 Cluster”, Z. Phys. D, 26: 304-306 (1993).
• Jellinek, J., Güvenç, Z.B., The Senergy Between Dynamics and Reactivity at Clusters and Surfaces, ed. L.J. Farrugta, Kluwer Academic Pub., Dortrecht, 217-240 (1995). [11] Sugano, S., Nishina, N., Ohnishi, S., ‘‘Microclusters’’, Springer-Verlag, Berlin, 98-105 (1987).
• Stave, M.S., DePristo, A.E.,‘‘The structure of NiN and PdN clusters 4=N=23’’, J. Chem. Phys., 97 (5): 3386-3399 (1992).
• Christensen, O.B., “Energetics and structure of negatively charged Cu clusters”, Phys. Rev. B, 50: 1844-1847 (1994).
• Garcia-Rodeja, J., Rey, C.J.L., Gallego, L.J., Alanso, J.A., ‘‘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’’, Phys. Rev. B, 49: 8495-8498 (1994).
• Chen, B., Gomez, M.A., Sehl, M., Doll, J.D., Freeman, D.L., “Theoretical studies of the structure and dynamics of metal/hydrogen systems: Diffusion and path integral Monte Carlo investigations of nickel and palladium clusters”, J. Chem. Phys., 105: 9686-9694 (1996). [16] Foiles, M.S., Baskes, M.I., Daw, M.S., ‘‘Embedded-atom-method functions for the fcc metals Cu, Ag, Au, Ni, Pd, Pt and their alloys’’, Phys. Rev. B, 33: 7983-7991 (1986).
• Parks, E.K., Zhu, L., Ho, J., Riley, S.J., “The structure of small nickel clusters. I. Ni3–Ni15”, J. Chem. Phys., 100: 7206-7222 (1994).
• Brown, L., Gabrielse, G., “Geonium theory: Physics of a single electron or ion in a Penning trap”, Rev. Mod. Phys., 58: 233-311 (1986).
• Krückeberg, S., Schweikhard, L., Ziegler, J., “Decay pathways and dissociation energies of copper clusters, Cun + (2≤ n ≤25) Cun 2+ (15≤ n ≤25)”, J. Chem. Phys., 114: 2955-2962 (2001).
• Spasov, V.A., Lee, T.H., Ervin, K.M., “Threshold collision-induced dissociation of anionic copper clusters and copper cluster monocarbonyls”, J. Chem. Phys., 112: 1713-1720 (2000).
• Darby, S., Mortimer-Jones, T.V., Johnston, R.L., Roberts, C.,‘‘Theorical study of Cu-Au nanoalloy clusters using a genetic algorithm’’, J. Chem. Phys., 116: 1536-1550 (2002).
• Voter, A.F., ‘‘Embedded Atom Method Potentials for Seven FCC metals: Ni, Pd, Pt, Cu, Ag, Au and Al’’, Los Alamos Unclassified Report LA-UR, 93: 3901-3908 (1993).
• Kittel, C., ‘‘Introduction to Solid State Physics’’, John Wiley and Sons, USA, 96-97 (1986).