Theoretical Study of the Encapsulation of Li2Al4 Inside the Zigzag Single-Walled Carbon Nanotubes (SWNTs)

By using density functional theory calculations, we report a novel class of single-walled carbon nanotubes (SWNTs)-based peapod, formed by the interaction of Li2Al4 molecule with the inner surface of a series of zigzag (n, 0) SWNT (n = 12-16). The results indicate that the tube diameter, the kinds of Li2Al4, isomers and the orientation of the Li2Al4, molecule inside SWNTs determine the interaction between guest and host. The interaction of CS and D-4h isomers with SWNTs is selective: the binding energies of D-4h isomer are more exothermic than those of the C-s isomer when the two kinds of isomers are encapsulated into the (12, 0) and (13, 0) tubes, while the binding energy of C-s isomer encapsulated inside the (14, 0), (15, 0), and (16, 0) tubes is larger than that of the encapsulated DO isomer. Moreover, we take Li2Al4(C-s)-encapsulated inside the (16, 0) tube as an example to perform an energy decomposition analysis and study the electronic properties of this novel peapods. On the other hand, the aromaticity of guest molecules can still be maintained, characterized by the planar structures and three sets of delocalized orbitals (two sigma and one pi) of Al-4(2-) units in Li2Al4@SWNTs peapods. Our results may be helpful to design nano-based composites with special characteristics.