Energetics and electronic structure of acetylene molecules encapsulated inside a carbon nanotube: A density functional theory study

Abstract We study the energetics of a single acetylene (C2H2) molecule inside single-walled carbon nanotubes (SWCNT) using first principles total energy calculations. We have found that energetically it is not favorable for the acetylene molecule to be encapsulated in the smallest nanotubes: our results suggest an energetic preference for acetylene to be enclosed in nanotubes wider than the (5,5) tube. This result is similar to the case of the adsorption of poly-acetylene on SWCNT. We have also studied the local density of states for the molecule-nanotube system, and found little effect of the acetylene molecule on the nanotube LDOS close to the Fermi Level.