Microscopic Growth Mechanisms for Carbon Nanotubes

• DOI: 10.1126/science.275.5300.647
• Publication Date: 2002-07-27T09:45:15Z
• Authors: Jean-Christophe C...; Alessandro De Vita; Xavier Blase; Roberto Car
• Keywords: Coaxial; Metastability; Chemisorption; Carbon fibers; Carbon nanobud

The uncatalyzed edge growth of carbon nanotubes was investigated by first-principles molecular dynamics simulations. At experimental temperatures the open end single-walled closed spontaneously into a graphitic dome, which may explain why these do not grow in absence transition metal catalysts. On other hand, chemical bonding between edges adjacent coaxial tubes (“lip-lip” interactions) trapped double-walled nanotube metastable energy minimum, thus preventing dome closure. These calculations show that this geometry exhibits high degree activity and easily accommodates incoming fragments, supporting model chemisorption from vapor phase.