PHYS 673 |
| The structural and electronic characteristics of fully hydrogenated carbon and boron nitride nanotubes have been determined by periodic B3LYP calculations. With use of line group symmetries, single-walled nanotubes up to 10 nm in diameter were systematically studied. Full exo-hydrogenation is most favourable for nanotubes with small diameters. Partial endo-hydrogenation, or “in-out” isomerism, stabilizes larger nanotubes, the optimal ratio of endo- to exo-hydrogens being 1:1. The stabilities of the favored carbon nanotubes increase as a function of the diameter of the tube while the analogous boron nitride nanotubes prefer structures with diameters of 3.5 nm. Accordingly, the hydrogenated diamond (111) sheet, i.e. the endo-exo hydrogenated carbon nanotube of infinite diameter, represents the strain free structure for CH stoichiometry. The analogous sheet of boron nitride prefers to bend, favoring curved structures such as nanotubes. The band gaps indicate the perhydrogenated nanotubes of carbon and boron nitride to be insulators.
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Nanostructured Materials
8:20 AM-12:00 PM, Thursday, April 10, 2008 Morial Convention Center -- Rm. 338/339, Oral
Division of Physical Chemistry |
