Abstract
Aniline is subjected to molecular modeling calculations at three levels namely HF/3-21G**, B3LYP/3-21G** and B3LYP/6-31G(d,p). According to the comparison between theoretically calculated vibrational spectra at each level and FTIR experimental spectra, results indicated that the B3LYP/3-21G** and B3LYP/6-31G(d,p) results are comparable, and that B3LYP/3-21G** results were obtained in a reasonable computational time. Polyaniline is then supposed to be put up on silicon substrate and decorated with 3 ZnO molecules to form silicon/polyaniline emeraldine base/3ZnO nanocomposite. Molecular electrostatic potential (ESP) showed uniform distribution, which changes as far as this nanocomposite is interacting with natural gas molecules. Another change is indicated in the total dipole moment (TDM) and HOMO/LUMO band gap energy as the polyaniline nanocomposite interacts with natural gas. The change in the physical properties of the studied nanocomposite dedicated it as sensor for natural gas.