Structural and electronic properties of carbon nanotubes

The structural and electronic properties of optimized open-ended single-wall carbon nanotubes with zigzag geometry have been investigated. The calculations were performed using molecular mechanics, extended Huckel, and AM1-RHF semiempirical molecular orbital methods. it has been found that the density of states of the zigzag model is sensitive to the tube size and changes as the tube length increases. On the other hand the energetics of the tube shows an almost linear dependence to the tube length, and a converging characteristics with respect to the number of hexagons forming the tube.