Abstract
The behavior and electronic structure of the carbon and boron nitride nanotubes that interact with the iron atom were studied using the Lennard-Jones potential and hybrid discrete-continuum approach. The iron-filled nanotubes were explored by means of classical applied mathematics in order to develop an understanding of the underlying mechanisms of the encapsulation of metal atoms inside nanotubes. Herein, we examined the suction energy and then the equilibrium offset positions of the iron atoms inside zigzag and armchair single-walled nanotubes, to obtain the optimal radii of the tubes and encapsulate the iron atom by determining the radii that provide the minimum interaction energies. Our observations indicate that the encapsulation behaviour depends on the radii of the nanotubes, and we predict that it is less likely for an iron atom to be enclosed inside the nanotubes when the value of the tube radius is less than approximate to 2.5 angstrom. The optimal nanotube necessary to fully enclose the iron atom has a radius of approximate to 4.2 for both carbon and boron nitride nanotubes, which approximately corresponds to the interaction energies of -1.8 kcal/mol. In its entirety, this work presents an approach that might further the understanding of the encapsulation of metal atoms inside nanotubes.