Insight into electronic and structural properties of nLi@ $$\text {B}_{20}$$ B 20 ( $$\hbox {n}=1{-}9$$ n = 1 - 9 ) nanotubules: a computational study

Abstract

In this paper, we have theoretically focused on the doping of up to nine Li atoms to the double-ring $$\text {B}_{20}$$ nanotubule to reveal the electronic and structural features of the nLi@ $$\text {B}_{20}$$ ( $$\text {n}=1{-}9$$ ) molecules. The most stable species for each of the nLi@ $$\text {B}_{20}$$ ( $$\text {n}=1{-}9$$ ) molecules has been reported on the singlet or doublet potential energy surfaces through density functional theory (DFT). The calculated results show that the nLi@ $$\text {B}_{20}$$ ( $$\text {n}=1{-}9$$ ) molecules have high thermodynamic and chemical stabilities due to high values of the adsorption energy, −2.51 eV to −3.57 eV, and the HOMO–LUMO energy gap, 1.32 eV to 2.34 eV. Additionally, the values reported for deformation of the double-ring $$\text {B}_{20}$$ backbone, 0.10 eV to 4.29 eV, increase severely along with increasing number of the Li atoms in the nLi@ $$\text {B}_{20}$$ ( $$\text {n}=1{-}9$$ ) molecules. The NBO charges of positive values for the Li atoms along with those of negative values for the B atoms confirm the role of electron donor of the Li atom and electron acceptor of the B atom. Finally, we have not found any Li–Li interaction in the nLi@ $$\text {B}_{20}$$ ( $$\text {n}=1{-}9$$ ) molecules based on AIM analysis. Moreover, all reported Li–B interactions are weak and non-covalent. In the present study, we have systematically added up to nine Li atoms to the double-ring $$\text {B}_{20}$$ molecule to report electronic and structural properties of the most stable local minima for each nLi@ $$\text {B}_{20}$$ ( $$\hbox {n}=1{-}9$$ ) molecules on the singlet or doublet potential energy surfaces.