Structure and stability of copper clusters: A tight-binding molecular dynamics study
- S.N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake City, Kolkata 700098 (India)
In this paper we propose a tight-binding molecular dynamics with parameters fitted to first-principles calculations on the smaller clusters and with an environment correction, to be a powerful technique for studying large transition-metal/noble-metal clusters. In particular, the structure and stability of Cu{sub n} clusters for n=3-55 are studied by using this technique. The results for small Cu{sub n} clusters (n=3-9) show good agreement with ab initio calculations and available experimental results. In the size range 10{<=}n{<=}55 most of the clusters adopt icosahedral structure which can be derived from the 13-atom icosahedron, the polyicosahedral 19-, 23-, and 26-atom clusters, and the 55-atom icosahedron, by adding or removing atoms. However, a local geometrical change from icosahedral to decahedral structure is observed for n=40-44 and return to the icosahedral growth pattern is found at n=45 which continues. Electronic 'magic numbers' ( n=2, 8, 20, 34, 40) in this regime are correctly reproduced. Due to electron pairing in highest occupied molecular orbitals (HOMOs), even-odd alternation is found. A sudden loss of even-odd alternation in second difference of cluster binding energy, HOMO-LUMO (LUMO, lowest unoccupied molecular orbital) gap energy and ionization potential is observed in the region n{approx}40 due to structural change there. Interplay between electronic and geometrical structure is found.
- OSTI ID:
- 20641009
- Journal Information:
- Physical Review. A, Journal Name: Physical Review. A Journal Issue: 4 Vol. 69; ISSN 1050-2947; ISSN PLRAAN
- Country of Publication:
- United States
- Language:
- English
Similar Records
Magnetic behavior in Cr{sub 2}@Ge{sub n} (1≤n≤12) clusters: A density functional investigation
First-principles investigation on the electronic efficiency and binding energy of the contacts formed by graphene and poly-aromatic hydrocarbon anchoring groups