STUDY OF SMALL METALLIC NANOPARTICLES: AN AB-INITIO FULL-POTENTIAL MUFFIN-TIN ORBITALS BASED MOLECULAR DYNAMICS STUDY OF SMALL Cu CLUSTERS

Abstract

The equilibrium structures and cohesive energies of small Cun clusters using the full-potential muffin-tin orbitals (FP-LMTO) based molecular dynamics (MD) have been studied for n ≤ 9. The results obtained have been compared with other chemical methods. We propose the FP-LMTO-MD technique to be a useful starting point of more empirical methods which can efficiently deals with larger cluster sizes relevant for nanoparticles.

Structure and stability of copper clusters: A tight-binding molecular dynamics study

“…Experimentally the binding energies of the neutral clusters were derived from the dissociation energy data of anionic clusters from the TCID experiment [18] and using electron affinities from the PES experiment [16]. The inset figure shows that our calculated binding energies are in good agreement with those from DF-LDA [19] and our previous FP-LMTO [22] calculations. However, our binding energies are systematically overestimated, by an energy 0.53 ± 0.12 to 0.79 ± 0.22, than the experimental binding energies.…”

“…This is a characteristic of the LDA. In the present study, TB parameters have been fitted to the ab initio LDA calculations for very small calculations [22]. It is not surprising therefore that the binding energies are over-estimated.…”

“…The overall shape of the curve matches the anticipated trend: binding energy grows monotonically with increasing the cluster size. Inset of the Fig.2 (upper panel) shows the comparison of our calculated binding energy with the ab initio [19,22] and experimental [18] results. Experimentally the binding energies of the neutral clusters were derived from the dissociation energy data of anionic clusters from the TCID experiment [18] and using electron affinities from the PES experiment [16].…”

“…Here they serve as a test case for the calculation of larger clusters with n ≥ 10. In Table III we present a detailed comparison of binding energy per atom, difference in binding energy △E and average bond length r for n ≤ 9 with available experimental [18] and ab initio [19,21,22] results. We found, in agreement with experimental [16] and theoretical [19,20,21] results, very small copper clusters (Cu 3 , Cu 4 and Cu 5 ) prefer planer structures.…”

“…Akeby et al [21] used the configuration interaction (CI) method with an effective core potential (ECP) for n ≤ 10. In an earlier communication [22] we studied the small Cu n clusters for n ≤ 9 by using full-potential muffin-tin orbitals (FP-LMTO) technique.…”