Investigation of the molecular structure, electronic properties, AIM, NBO, NMR and NQR parameters for the interaction of Sc, Ga and Mg-doped (6,0) aluminum nitride nanotubes with COCl2 gas by DFT study

Abstract

In order to search for a novel sensor to detect and control exposure to phosgene (COCl2) molecule, the reactivities of pristine, Sc, Ga and Mg-doped (6,0) single-walled aluminum nitride nanotubes (AlNNTs) towards the COCl2 molecule are investigated by performing density functional theory calculations. It is found that the COCl2 molecule presents strong physisorption on the Mg and Sc-substituted Al defect sites, which is in contrast to its weak physisorption on pristine and Ga-doped AlNNTs. The AIM theory has been also used to examine the properties of the bond critical points: their electron densities and Laplacians. The nature of charge transfer between the oxygen atom of COCl2 and the impurity atoms is clarified. Natural bond orbital analysis reveals that the electronic configuration of the doped Mg metal represents a prominent change with respect to that of the Sc and Ga atoms. Also, the interaction of COCl2 gas and pristine/doped AlNNTs on the basis of four reactivity descriptors such as the overall stabilization energy (ΔESE), the individual energy change of acceptor (ΔEA(B)), the individual energy change of donor (ΔEB(A)) and charge transfer (ΔN) have been explained. We found that substituting an Al atom by Mg makes the electronic properties of the AlNNT strongly sensitive to the COCl2 molecule. Due to physisorption, NMR and NQR parameters of the adsorption sites are also altered. Density of the state investigation suggests that the Mg doping induces main changes in the electronic structure pattern of the interaction of phosgene gas with AlNNT.