Molecular mechanics of structural properties of boron nitride nanotubes

The optimized structure of boron nitride nanotubes is investigated, based on the Universal force field. Bond length, diameter deviation, and buckling of boron nitride nanotubes increase with decreasing diameter. This is caused by different hybridizations of boron and nitrogen in the curved surface. Strain energy also decreases, which is proportional to the inverse square of the tube diameter, with larger diameter on the basis of continuum elastic theory.