Inapplicability of small-polaron model for the explanation of infrared absorption spectrum in acetanilide.

The applicability of small-polaron model for the interpretation of infrared absorption spectrum in acetanilide has been critically reexamined. It is shown that the energy difference between the normal and anomalous peak, calculated by means of small-polaron theory, displays pronounced temperature dependence which is in drastic contradiction with experiment. It is demonstrated that self-trapped states, which are recently suggested to explain theoretically the experimental absorption spectrum in protein, cannot cause the appearance of the peaks in absorption spectrum for acetanilide.

Finite-temperature large acoustic polaron dynamics in quasi-one-dimensional molecular crystals.

We report the results of theoretical examinations of large polaron motion in one-dimensional (1D) molecular crystals under the influence of thermal fluctuations of the host lattice and constant electric field. Such a situation may arise in biological macromolecules such as an alpha helix where charge (electron) transfer may be achieved by a polaron (soliton) mechanism. In that case, the electric field represents the effective endogenous electric field which is always present in realistic conditions.