A QTAIM approach on poly tetrahydrothiophene molecular wire

The present investigation of structural, charge density and electrical characteristics of Au and thiol substituted poly tetrahydrothiophene molecular wire by using quantum chemical calculations has been carried out with density functional theory (DFT). The various applied electric field (0.00 – 0.26 VÅ-1 ) altered the geometrical parameters and the corresponding electrostatic and transport properties of the molecule has been analyzed. Interstingly, the applied electric field is increased from 0 eV, the Au−S bond distance at the right terminal is faintly longer than the left end; this variation is resulted from the gold atom at the left end which practices stronger electric field when compared with at the right end of TET molecule. The variations in the atomic charges (MPA, NPA) of the molecule for the various applied electric fields have been compared. The HOMO-LUMO gap of the molecule for zero bias is 1.96eV, as the field increases this gap decrease to 1.31 eV. The ESP shows the potential difference between charges accumulated of the molecule for various applied electric field. The applied electric field polarizes the TET molecule; as a result dipole moment of the molecule rises from 2.47 to 15.33 D.