Mechanical properties of the complexes of carbon nanotube (7,7) with single $\mathrm{Li}$, $\mathrm{Na}$, $\mathrm{S}$ and $\mathrm{Se}$ atoms

Exo- and endohedral complexes of carbon nanotubes $(7,7)$ with small concentration(less than $\sim1$ at. %) of adsorbed atoms of the lithium, sodium, sulfur and selenium on their surface are considered. Equilibrium configurations of these complexes, as well as their mechanical properties (elastic moduli, tensile strength and elongation at break were calculated by using methods of first-principle simulations and density functional theory. The difference in influence of atoms of alkaline metals and chalcogen atoms on structure and properties of sorption complexes was shown.