A DFT, AIM and NBO study of adsorption and chemical sensing of iodine by S-doped fullerenes

In the present work, geometries, stabilities and electronic properties of simple and iodine adsorbed S-doped fullerenes (SFs) with parallel and perpendicular configurations were studied using density functional theory (DFT) calculations. The adsorption process was a little endothermic and iodine molecule could be adsorbed on the surface of SFs with Gibbs free energies of 6.33 to 26.70 kcal/mol. From the AIM calculations, the acceptable rho and positive (sic)(rho)(2) values confirmed efficient and non-covalent interaction between iodine and SFs. NBO analyses showed the powerful interaction between the doped sulfur and iodine. The DOS plot of SFs was different from that of the undoped fullerene; the HOMO/LUMO energy gap of SFs was between 0.061 and 0.071 eV while in the simple fullerene, it was 0.106 eV. Moreover, the decrease in E-g was found for their complexes with iodine and the results were in the range of 0.004-0.053 eV. Therefore, the electrical conductivity of the SFs was increased upon the iodine adsorption and the SFs could be used in sensor devices for iodine detection. (C) 2014 Elsevier B.V. All rights reserved.