Understanding the charge density distribution and the electrostatic properties of hexadecane molecular nanowire under electric field using DFT and AIM theory

Abstract

A theoretical charge density analysis on Au and thiol atoms terminated hexadecane (C16H32S2Au2) molecule has been carried out for zero and various applied electric fields using density functional theory (DFT) and Bader’s theory of atoms in molecules to determine the bond topological, electrostatic and transport properties. This is the first report about the characterization of hexadecane molecule on the basis of charge density and energy density distribution. On compared with the zero field, the conformation, charge density distribution and the electronic energy levels of the hexadecane molecule have been modified for the applied EFs (0.05–0.26VÅ−1). Further, the electric field decreases the HOMO–LUMO gap (HLG) significantly from 2.694 to 0.109eV and these values are almost equal to the energy gap obtained from density of states (DOSs) spectrum. The molecular electrostatic potential shows the effect of terminal Au and thiol atoms, and the external field in the molecule. The observed results are expected to be helpful to design and rationalize the performance of n-alkane chain based molecular nanowires.