Effect of tube radius on the exohedral chemical functionalization of boron-nitride zigzag nanotubes with NH3

The interaction between zigzag BNNTs with chirality index n=3-10 and ammonia has been studied at the level of B3LYP/6-31G⁎. Ammonia can be chemically adsorbed on (3,0) to (7,0) BNNTs and physically adsorbed on other studied BNNTs. From NBO analysis charge transfer occur from NH3 to BNNTs and change in the natural electron configuration of B atom of BNNTs at adsorption site for the (3,0) and (4,0) BNNTs cases is larger than others. The DOS result show that after functionalization of BNNTs with NH3 molecules electronic properties of tubes are largely preserved and can be viewed as some kind of harmless modification. Electronic analysis revealed that the interaction of zigzag BNNTs with ammonia is more electrostatic (ionic) in nature, rather than the sole covalent and electrostatic nature increased with increasing of tube diameter.