Study of Bond Length and Bond Angle with increase in Diameter of Single-walled Carbon Nanotubes

It is quite hard to study the structure of single-walled carbon nanotubes (SWCNT) directly because of their nanoscaled sizes. Thus we use computer simulation software to simulate the structures of SWCNT and measure the structural parameters, i.e., bond lengths and bond angles for different types of SWCNT and found that diameter have signi�cant effects on these bond lengths and bond angles. Results for (n, n) armchair tubes show that one bond length is greater than that of the other two bond lengths which are equal to each other. Two bond angles are same but different from third bond angle. Bond lengths expend with increase in tube diameter. Two bond angles start equally increasing but third one decreases with increase in tube diameter. In (n, 0) zigzag SWCNT, two bond lengths are same and decrease with increase in diameter. These bond lengths are different from third bond length which increases with increase in diameter. Two bond angles are equal and show no change on increasing tube diameter. Third bond angle starts increasing and become constant with increase in tube diameter. For (n, m) chiral SWCNT, bond lengths are different from each other and starts increasing with increase in tube diameter but beyond 1.053 nm diameter two bond lengths become constant and equal to each other. Two bond angles are decreased on increasing tube diameter but above 1.424 nm diameter one bond angle starts increasing. Third bond angle increases with increase in diameter of SWCNT tube.