Ab initio study of field evaporation from single-walled carbon nanotubes

We have performed partitioned real-space density functional (PRDF) calculations of field evaporation of carbon clusters from single-walled carbon nanotubes (SWNT). The calculation results of the activation-energy barrier (AEB) for field evaporation of carbon clusters and hydrocarbon clusters from SWNT’s show that the AEB decreases as the electric field increases, and that the atom-relaxation effect largely reduces the AEB. It is also found that evaporation from an open-ended carbon nanotube occurs more easily than from capped nanotubes owing to the difference in the number of C-C bonds between the two types of nanotubes. Most surprisingly, adsorbed hydrogen significantly reduces the AEB. This is clearly explained by the C-C bond weakening due to the adsorbed hydrogen.