Effects of distance dependence of exciton hopping on the Davydov soliton

Abstract

The Davydov model of energy transfer in molecular chains is reconsidered assuming the distance dependence of the exciton hopping term. New equations of motion for phonons and excitons are derived within the coherent state approximation. Solving these nonlinear equations result in the existence of Davydov-like solitons. In the case of a dilatational soliton, the amplitude and width is decreased as a results of the mechanism introduced here and above a critical coupling strength our equations do not allow for localized solutions. For compressional solitons, stability is increased.Comment: RevTeX 13 pages, 3 Postscript figure

Mobility of discrete multibreathers in the exciton dynamics of the Davydov model with saturable nonlinearities

“…Based on the meaning of the sign of χ [31], it appears that negative coefficient means that the molecular chain is locally dilated (dilatational soliton) and a positive value represents the local compression (compressional soliton) of molecular chain due to amide-I vibrations. It follows that our model exhibits a competition of self-focusing (dilatation) and defocusing (compression) saturable nonlinearities.…”

Solitons in Alpha-Helix Proteins by He's Variational Principle

“…For cubic law nonlinearity, the appropriate form of the soliton is given by [1,2] g(s) = A cosh(Bs) (18) and so J, from (17), simplifies to…”

“…The energy and charge transport in biological systems is an important problem that became clear in 1973 when Davydov proposed a model for the energy transport in quasi one-dimensional biological systems [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Transport of biological energy is carried out by the so-called Davydov solitons which freely travel through the system [9].…”

Energy Sharing Mechanism of a Higher Order Protein System

“…Davydov [1-3] asserts that the soliton is created by the exciton's selftrapping, which results from the energy released during ATP hydrolysis interacting with the vibration of amino acid molecules in the protein. A lot of problems related to the Davydov model have been extensively studied [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] in the recent past. Dynamical properties of Davydov solitons and their formation given various initial conditions of the chain have been investigated in discrete chains and in continuum models.…”