Date of Award
Master of Science
Interdisciplinary Studies (Sci)
The electronic properties of Al clusters containing up to 60 atoms are investigated using an all electron density functional theory using large polarized Gaussian basis sets with 39 Gaussians per atom (NRLMOL basis). We have performed an extensive search for the lowest energy isomers for clusters up to Al 21. We build a database of candidate structures for the ground state using different strategies. First, a few structures are randomly generated and fully relaxed using plane wave pseudo potential method. We also performed simulated annealing runs using ab initio molecular dynamics for clusters up to Al20. In three sets of simulated annealing runs the clusters were heated up to 900 and 1000K and were slowly cooled to 50K at different rates. After every half pico second, the cluster was quenched. Additionally the best basin hopping geometries obtained using empirical embedded atoms potential were also fully optimized. The process generates 40-50 structures for each size. All the structures are relaxed using full potential PAW method using a large energy cutoff. For larger clusters we used best available geometries from literature obtained from basin hopping and simulated annealing techniques. The electronic properties of Al clusters are subsequently determined for this database at the all-electron level using Gaussian basis set.
Received from ProQuest
Raparla, Mrudula, "Structural and electronic properties of Aluminum Nano Clusters by DFT" (2010). Open Access Theses & Dissertations. 2762.