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 International Conference on Complex Systems (ICCS2007)

Physical Nanoparticles with Small-World Properties: DFT calculations

Jeremy Yancey
Department of Physics and Astronomy, Mississippi State Unive

Mark Novotny
Mississippi State University, Mississippi State University

Steven Gwaltney
Department of Chemistry, Mississippi State University

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     Last modified: October 15, 2007

We have performed large-scale Density Functional Theory (DFT) calculations of carbon nanoparticles to determine whether or not nanoparticles with small-world properties can be stable. Although we have previously shown that nanoparticles with small-world connections cannot exist, nanoparticles with physical small-world connections can be stable and should have small-world properties. The DFT calculations used are a B3LYP exchange-correlation functional and a 6-31G* basis set. Our pseudo-small-world nanoparticles are compared with other all-carbon nanoparticles, including rings, rods, and various fullerenes including C.20 and C.60. Our (pseudo) small-world nanoparticles start with a ring of carbons, and then small-world connections are added to the ring (with the constraint that each carbon atom has at most four bonds). The physical connections are made by adding additional carbon atoms to the small-world links. The small-world networks were constructed using Spartan, then relaxed to a reasonable starting geometry using a MMFF94 force field optimization, and finally were optimized using DFT calculations. We have considered only nanoparticles that are stable in the DFT calculations, and so should be able to exist in nature. We demonstrate that some pseudo-small-world all-carbon nanoparticles are indeed stable. In particular, we have extensively studied the case of N-atom rings with one and two small-world connections. Furthermore, we have some nanoparticles that have a very high density of small-world connections with respect to the number of ring atoms. We present both NMR and vibrational spectra for these nanoparticles. [ Download Full Text of this Paper]

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