Structural and electronic properties of carbon nanotubes

The structural and electronic properties of optimized open-ended single-wal l carbon nanotubes with zigzag geometry have been investigated. The calcula tions were performed using molecular mechanics, extended Huckel, and AM1-RH F semiempirical molecular orbital methods. it has been found that the densi ty 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 char acteristics with respect to the number of hexagons forming the tube.