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Technical Report CMS-TR-20051108


Title Finite-Temperature Behavior of Small Silicon and Tin Clusters: An Ab Initio Molecular Dynamics Study
Author/s Sailaja Krishnamurty
Centre for Modeling and Simulation, Savitribai Phule Pune University, Pune 411 007 India


Kavita Joshi
Department of Physics, Savitribai Phule Pune University, Pune 411 007 India


D. G. Kanhere
Centre for Modeling and Simulation, Savitribai Phule Pune University, Pune 411 007 India
Abstract The finite-temperature behavior of small silicon and tin clusters (Si10, Si15, Si20, Sn10, and Sn20) is studied using isokinetic Born-Oppenheimer molecular dynamics. We find that the low-lying structures for all the clusters are built upon a highly stable tricapped trigonal prism unit which is seen to play a crucial role in the finite-temperature behavior. The thermodynamics of small tin clusters is revisited in light of the recent experiments on tin clusters of sizes 18–21 [G. A. Breaux et al., Phys. Rev. B, 71, 073410 (2005)]. Our calculated heat capacities for Si10, Sn10, and Si15 show main peaks around 2300, 2200, and 1400  K, respectively. The finite-temperature behavior of Si10 and Sn10 is dominated by isomerization and it is rather difficult to discern their melting temperatures. On the other hand, Si15 does show a liquidlike behavior over a short temperature range, which is followed by fragmentation observed around 1800  K. The finite-temperature behavior of Si20 and Sn20 shows that these clusters do not melt but fragment around 1200 and 650  K, respectively.
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Citing This Document Sailaja Krishnamurty, Kavita Joshi, and D. G. Kanhere , Finite-Temperature Behavior of Small Silicon and Tin Clusters: An Ab Initio Molecular Dynamics Study . Technical Report CMS-TR-20051108 of the Centre for Modeling and Simulation, Savitribai Phule Pune University, Pune 411007, India (2005); available at http://cms.unipune.ernet.in/reports/.
Notes, Published Reference, Etc. Published as Physical Review B 73, 045419 (2006)
Contact kanhere AT unipune.ac.in
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