Conformational soliton

Soliton — Solitons (solitary waves) are neutral or charged quasiparticles which were introduced in solid state physics in order to describe the electron-phonon coupling. In one-dimensional chainlike structures there is a strong coupling of the electronic states to conformational excitations (solitons), therefore, the concept of soliton (-> polaron, - bipolaron) became an essential tool to explain the behavior of - conducting polymers. While in traditional three-dimensional -> semiconductors due to their rigid structure the conventional concept of - electrons and -> holes as dominant excitations is considered, in the case of polymers the dominant electronic excitations are inherently coupled to chain distortions [i]. 

Conformational Solitons in DNA and Their Possible Role in Cancer Initiation... 

Soliton (Fig. 2c) is a term used by physicists in various connections. From the chemist s point of view, a soliton is a positive, negative, or neutral radical-like site and corresponding conformational kink in the simple conjugated system of polyacetylene separating two semiinfinite conjugated chains. As with the polaron and bipolaron in other CPs, the soliton is mobile in the chain and is thought to be the charge carrier in poly acetylene. 

Phthalocyanine and their polymers possessing cyan and carboxyl terminals have suitable extended con-jugateds structures that facilitate solitonic, polaronic and bipolaronic conformational deformations and hence are expected to show large ultra fast non-linear... 

Further possibilities for long-range effects of chemical carcinogens are provided by the change or occurrence of different collective states in these complex polymers. These collective states can be vibrational or conformational solitons, Mott insulator states, Peierls instabilities, plasmon-type states, charge and spin density waves, excitonic insulator states, etc. Here only one example (which has been worked out in some detail), namely a conformational soliton caused by carcinogen binding, will be discussed. 

---