Nonlinear Migration Dynamics of Excess Electrons along Linear Oligopeptides Controlled by an Applied Electric Field

Abstract Migration of an excess electron along linear oligopeptides governed by the external electric field (E ex ) which is against the inner dipole electric field is theoretically investigated, including the effects of E ex on the structural and electronic properties of electron migration. Two structural properties including electron‐binding ability and the dipole moment of linear oligopeptides are sensitive to the E ex values and can be largely modulated by E ex due to the competition of E ex and the inner electric field and electron transfer caused by E ex . In the case of low E ex values, two structural properties decrease slightly , while for high E ex values, the electron‐binding ability continually increases strongly, with dipole moments firstly increasing significantly and then increasing more slowly at higher E ex . Additionally, linear oligopeptides of different chain lengths influence the modulation extent of E ex and the longer the chain length is, the more sensitive modulation of E ex is. In addition, electronic properties represented by electron spin densities and singly occupied molecular orbital distributions vary with E ex intensities, leading to an unusual electron migration behavior. As E ex increases, an excess electron transfers from the N‐terminus to the C‐terminus and jumps over a neighboring dipole unit of two termini to other units, respectively, instead of transferring by means of a one‐by‐one dipole unit hopping mechanism. These findings not only promote a deeper understanding of the connection between E ex and structural and electronic properties of electron transfer behavior in peptides, but also provide a new insight into the modulation of electron migration along the oligopeptides.