High pressure synthesis of the carbon allotrope hexagonite with carbon nanotubes in a diamond anvil cell

In a previous report, the approximate crystalline structure and electronic structure of a novel, hypothetical hexagonal carbon allotrope has been disclosed. Employing the approximate extended Huckel method, this C structure was determined to be a semi-conducting structure. In contrast, a state-of-th...

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Detalles Bibliográficos
Autores principales: Bucknum, Michael J., Castro, Eduardo Alberto
Formato: Libro Capitulo de libro
Lenguaje:Inglés
Publicado: Springer 2011
Materias:
Química
Diamond Anvil Cell
Density functional theory
Infinite Family
Carbon Allotrope
Ultrasoft Pseudopotentials
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/146059
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-146059
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Química
Diamond Anvil Cell
Density functional theory
Infinite Family
Carbon Allotrope
Ultrasoft Pseudopotentials
spellingShingle Química
Diamond Anvil Cell
Density functional theory
Infinite Family
Carbon Allotrope
Ultrasoft Pseudopotentials
Bucknum, Michael J.
Castro, Eduardo Alberto
High pressure synthesis of the carbon allotrope hexagonite with carbon nanotubes in a diamond anvil cell
topic_facet Química
Diamond Anvil Cell
Density functional theory
Infinite Family
Carbon Allotrope
Ultrasoft Pseudopotentials
description In a previous report, the approximate crystalline structure and electronic structure of a novel, hypothetical hexagonal carbon allotrope has been disclosed. Employing the approximate extended Huckel method, this C structure was determined to be a semi-conducting structure. In contrast, a state-of-the-art density functional theory (DFT) optimization reveals the hexagonal structure to be metallic in band profile. It is built upon a bicyclo[2.2.2]-2,5,7-octatriene (barrelene) generating fragment molecule, and is a Catalan network, with the Wells point symbol (6⁶)₂(6³)₃ and the corresponding Schlafli symbol (6, 3.4). As the network is entirely composed of hexagons and, in addition, possesses hexagonal symmetry, lying in space group P6/mmm (space group #191), it has been given the name hexagonite. The present report describes a density functional theory (DFT) optimization of the lattice parameters of the parent hexagonite structure, with the result giving the optimized lattice parameters of a = 0.477 nm and c = 0.412 nm. A calculation is then reported of a simple diffraction pattern of hexagonite from these optimized lattice parameters, with Bragg spacings enumerated for the lattice out to fourth order. Results of a synchrotron diffraction study of carbon nanotubes which underwent cold compression in a diamond anvil cell (DAC) to 100 GPa, in which the carbon nanotubes have evidently collapsed into a hitherto unknown hexagonal C polymorph, are then compared to the calculated diffraction pattern for the DFT optimized hexagonite structure. It is seen that a close fit is obtained to the experimental data, with a standard deviation over the five matched reflections being given by σx = 0.003107 nm/reflection.
format Libro
Capitulo de libro
author Bucknum, Michael J.
Castro, Eduardo Alberto
author_facet Bucknum, Michael J.
Castro, Eduardo Alberto
author_sort Bucknum, Michael J.
title High pressure synthesis of the carbon allotrope hexagonite with carbon nanotubes in a diamond anvil cell
title_short High pressure synthesis of the carbon allotrope hexagonite with carbon nanotubes in a diamond anvil cell
title_full High pressure synthesis of the carbon allotrope hexagonite with carbon nanotubes in a diamond anvil cell
title_fullStr High pressure synthesis of the carbon allotrope hexagonite with carbon nanotubes in a diamond anvil cell
title_full_unstemmed High pressure synthesis of the carbon allotrope hexagonite with carbon nanotubes in a diamond anvil cell
title_sort high pressure synthesis of the carbon allotrope hexagonite with carbon nanotubes in a diamond anvil cell
publisher Springer
publishDate 2011
url http://sedici.unlp.edu.ar/handle/10915/146059
work_keys_str_mv AT bucknummichaelj highpressuresynthesisofthecarbonallotropehexagonitewithcarbonnanotubesinadiamondanvilcell
AT castroeduardoalberto highpressuresynthesisofthecarbonallotropehexagonitewithcarbonnanotubesinadiamondanvilcell
bdutipo_str Repositorios
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