IIIT Hyderabad Publications |
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Density Functional Theory and Genetic Algorithm based studies of Gold clusters and Doped Gold clustersAuthor: LOVEPREET SINGH sindhu Date: 2017-08-09 Report no: IIIT/TH/2017/43 Advisor:Harjinder Singh AbstractGold clusters have attracted a lot of interest due to the discovery of their unique catalytic properties and their unique optical properties that give them great potential for medical applications. Small gold clusters serve as models for understanding the molecular processes taking place during catalysis. Along with pristine clusters, role of doped clusters has also gained an intense interest. Strong modulation of the physiochemical properties of metal clusters due to doping has made doped clusters potential candidates in sensing, catalysis and medicine industries. This needs a detailed understanding of the structural and physicochemical properties of the system which are in turn dependent on the electronic properties. In this work, the perturbation of doping atoms, belonging to the alkali and alkaline earth metal groups, on the Au10 cluster has been unraveled by studying the electronic structure and stability of these metal clusters. Our density functional theory based calculations show that a planar to 3D transition can be induced in Au10 by doping it with a dopant of large atomic radius. These dopants lead to electronic modulation of the cluster resulting in better charge transfer potential which is quantified by analyzing the HOMO-LUMO gaps, vertical electron affinity and ionization potential of the pristine and doped cluster. An attempt to locate the energetically minimum structures in case of Aun clusters (n=2- 9) was also carried out using density functional theory and our recently developed genetic algorithm code coupled with GAMESS. PBE0 functional and high quality basis set were employed for carrying out all the calculations related to geometry and electronic modulation of small gold clusters. The main motive of this study was to study the change in properties of gold clusters as size of cluster varies and also cover more sample space and get the minimum energy structures in very less time. So we experimented it with genetic algorithm. This study attempts to provide an insight into how structural and electronic properties vary according to different-sized gold clusters and also portrays that doped clusters can be better potential candidates for use as heterogeneous catalysts, where the dopants serve as tools to tune the catalytic efficiency of the system. Full thesis: pdf Centre for Computational Natural Sciences and Bioinformatics |
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