Disintegration of finite carbon chains in electric fields

We use the density functional formalism to investigate the stability and disintegration of finite carbon chains in electric fields. Carbon chains are very stable, since they require energies in excess of 5 eV to fragment. Only in strong electric fields exceeding 4 V/Angstrom, we find neutral chains to disintegrate, preferably by field emitting a monomer from the negatively polarized end. This critical field for fragmentation is found to decrease in chains that carry a net negative charge. We discuss the impact of these results on the evolution of atomic structures at the tip of carbon nanotubes grown in the carbon are.