Influence Of Interchain Coupling Research Articles

On the vibron nature in the system of two parallel macromolecular chains: The influence of interchain coupling

We studied the properties of the intramolecular vibrational excitation (vibron) at finite temperature in a system which consists of two parallel macromolecular chains. It was assumed that vibron interacts exclusively with dispersionless optical phonons and the whole system is considered to be in thermal equilibrium. Particular attention has been paid to the examination of the impact of the temperature and strength of the interchain coupling on the small polaron crossover. For that purpose we employed partial dressing method which enables the study of the degree of the phonon dressing of the vibron excitations in a wide area of system parameter space. We found that in the non-adiabatic regime the degree of dressing as a function of coupling constant continuously increases reflecting the smooth transition of the slightly dressed, practically free vibron, to a heavily dressed one: small polaron. As “adiabaticity” rises this transition becomes increasingly steeper, and finally, in the adiabatic limit, a discontinuous “jump” of the degree of dressing is observed. The interchain coupling manifests itself through the increase of the effective adiabatic parameter of the system.

Influence of interchain coupling on localized excitations in a model of conducting polymers

Using the SSH-Hamiltonian extended to two coupled chains the time evolution of the electronic density matrix was numerically treated in mean-field approximation. The dynamics of charge transfer complexes composed of a transverse polaron or electronhole pair is discussed. An electron-hole pair at one chain is found to be transferred as a soliton pair to a neighbouring chain.

Pressure Dependence of Photoluminescence of Oligothiophenes

AbstractWe report on the nature of emitting states in two different quaterthiophenes: the unsubstituted quaterthiophenes (T4) and a bridged T4 (T4B), where the bridging have been realized by introducing a second bond between the two central thiophene rings. The effect of the chemical bridging on the photophysics of these compounds have been studied via photoluminescence measurements under hydrostatic pressure, which permit to clarify the influence of interchain coupling, conformational effects and intrachain structural changes on the optical properties.

Influence of interchain coupling on the one-dimensional magnon raman spectrum of CsCoBr 3

Light scattering from magnons in CsCoBr 3 has been measured for temperatures well below the upper antiferromagnetic 3D ordering temperature of T l N = 28 K. These experiments reveal multiple magnon features of energies in the range 90 to 170 cm -1 similar to those found in CsCoCl 3 but previously unobserved for the bromide. Prominent features in the spectrum and their temperature dependence are described in terms of a recent theory by Shiba. Other, weaker features are explained by a simple extension of the theory to include fluctuations. A new band is observed at 178 cm -1, whose intensity drops sharply prior to the lower 3D ordering transition at T ∥ N = 10 K. This band is assigned to magnon-phonon combination scattering.

Influence of interchain coupling on the one-dimensional magnon Raman spectrum of CsCoBr 3

Light scattering from magnons in CsCoBr 3 has been measured for temperatures well below the upper antiferromagnetic 3D ordering temperature of T l N = 28 K. These experiments reveal multiple magnon features of energies in the range 90 to 170 cm -1 similar to those found in CsCoCl 3 but previously unobserved for the bromide. Prominent features in the spectrum and their temperature dependence are described in terms of a recent theory by Shiba. Other, weaker features are explained by a simple extension of the theory to include fluctuations. A new band is observed at 178 cm -1, whose intensity drops sharply prior to the lower 3D ordering transition at T l N = 10 K. This band is assigned to magnon-phonon combination scattering.