Conformational analysis of diphenylacetylene under the influence of an external electric field

Abstract

Theoretical investigation of the torsional potentials of a molecular wire, diphenylacetylene, was carried out at the B3LYP/6-311+G** level by considering the influence of the external electric field (EF). It demonstrates that many molecular features are sensitive to the EF applied. In particular, the torsional barrier increases and the LUMO–HOMO gap decreases with the increase of EF. Quantitative correlations between these features and the external EF were revealed. The current–voltage behavior corresponding to different conformers was studied as well by non-equilibrium Green’s function method combined with the density functional theory. Further, the evolution of the LUMO-HOMO gap and the spatial distribution of molecular orbital were used to analyze these structure–property relationships.