Structure of Graphene, and Mechanical and Bonding Characteristics of Single Wall Carbon Nanotube by Linear Scaling Quantum Mechanical Method

Using a linear scaling self-consistent-charge density functional tight binding (SCC-DFTB) and an ab initio Dmol method, the bonding characteristics and Young's modulus of (10, 0) and (10,10) single-walled carbon nanotubes are calculated. The structure of a graphene is also calculated. It is found that the C-C and C-H bond length, their distribution characteristics on the tube, and Young's modulus of the tube by linear scaling SCC-DFTB are identical to those by ab initio, while the computing cost by the linear scaling SCC-DFTB is reduced by more than 30 times as compared with that by the Dmol for the (10,0) and (10,10) tubes By computing the structure of a graphene it is also found that the linear scaling SCCDFTB is reliable and time-saving.