The effect of surface curvature of aluminum nitride nanotubes on the adsorption of NH3

Our main objectives are to address the following fundamental issues: (1) A density functional theory study on the structural and electronic properties of the zigzag single-walled aluminum nitride nanotubes (AlNNTs) with various diameters, using B3LYP/6-31G* level of theory. (2) An ONIOM study on the curvature effect of AlNNTs on the NH3 adsorption process using B3LYP/6-31G* and semi-empirical AM1 approaches. Furthermore, a potential energy surface is calculated for NH3 moving toward AlNNT surface. In contrast to semiconducting carbon nanotubes (Louie, Top Appl Phys 80:113, 2001) our calculations confirmed that the HOMO-LUMO energy gap of AlNNTs increases with an increase of the tube diameter. Additionally, we showed that HOMO/LUMO interaction between NH3 and AlNNTs becomes stronger as the tube diameter decreases.