Energetics, structure, mechanical and vibrational properties of single-walled carbon nanotubes

. In this paper, we present extensive molecular mechanics and molecular dynamics studies on the energy, structure, mechanical and vibrational properties of single-wall carbon nanotubes. In our study we employed an accurate interaction potential derived from quantum mechanics. We explored the stability domains of circular and collapsed cross section structures of armchair (n, n), zigzag (n, 0), and chiral (2n, n) isolated single-walled carbon nanotubes (SWNTs) up to a circular cross section radius of 170 A. We have found three different stability regions based on circular cross section radius. Below 10 A radius only the circular cross section tubules are stable. Between 10 and 30 A both circular and collapsed forms are possible, however, the circular cross section SWNTs are energetically favorable. Beyond 30 A (crossover radius) the collapsed form becomes favorable for all three types of SWNTs. We report the behavior of the SWNTs with radii close to the crossover radius ((45...