https://doi.org/10.1140/epjd/e2009-00235-1
Structural and electronic properties of Snn-1Pb and Pbn-1Sn clusters: a theoretical investigation through first principles calculations
1
Department of Materials Science, Indian Association for the
Cultivation of Science, Jadavpur, 700032 Kolkata, India
2
RMC, Bhabha Atomic Research Centre, 400085 Mumbai, India
3
Chemistry Division, Bhabha Atomic Research Centre, 400085 Mumbai, India
Corresponding author: a chimaju@barc.gov.in
Received:
26
March
2009
Revised:
29
June
2009
Published online:
4
September
2009
Here we report a systematic theoretical study of the structure and electronic properties of Snn-1Pb and Pbn-1Sn (n = 2-13) clusters and compare these results with pure Snn and Pbn to understand the influence of the dopant elements. The calculations were carried out using the density functional theory with generalized gradient approximation for the exchange-correlation potential. Extensive search based on large number of initial configurations has been carried out to locate the stable isomers of Snn-1Pb and Pbn-1Sn (n = 2-13) clusters. The relative stability of Snn-1Pb and Pbn-1Sn (n = 2-13) clusters is analyzed based on the calculated binding energies and second difference in energy. The stability analysis of these clusters suggests that, while the substitution of Sn by Pb lowers the stability of Snn clusters, presence of Sn enhances the stability of the Pbn clusters. The results suggest that while for Snn-1Pb, n=4, 7, 10, 12 clusters are more stable than their respective neighbors, Pbn-1Sn clusters with n = 4, 7 and 9 are found to be more stable. Based on the fragmentation pattern it is seen that for Snn-1Pb and Pbn-1Sn clusters favor monomer evaporation of the Pb atom up to n =11 and n =12, respectively. Unlike this trend, the Sn11Pb undergoes fission type fragment into Sn5Pb and Sn6 clusters. A comparison between our theoretical results and surface induced dissociation experiment shows good agreement, which gives confidence on the prediction of the ground state geometries.
PACS: 73.22.-f – Electronic structure of nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals / 36.40.Cg – Electronic and magnetic properties of clusters / 36.40.Qv – Stability and fragmentation of clusters / 36.40.Ei – Phase transitions in clusters
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2009