Electronic properties of polyenes and polyphenylacetylenes

Quantum-chemical studies of quasi-one-dimensional electron systems. 1. Polyenes

“…This was repeatedly proved experimentally by the ESR method [30][31][32]. A satisfactory explanation of the general regularities of this phenomena is possible in terms of the local defect centers and the charge transfer between macromolecules [29,[33][34][35][36][37]. In particular it was suggested [29] that an experimentally observed ESR signal in long conjugated systems may be connected with an appearance of a pair of defects of the type These defects have been interpreted [29] as radicals.…”

“…Substituting (10) into (31) Analysis of the appearance conditions having one or two solutions of (38) is analogous to the analysis of Eqs. (32) and (33). In fact, this analysis was based on the consideration of these equations in the limiting case where 0   which in the present case corresponds to an approach up to the edges of the allowed bands, that is (42) and can be solved by the iteration method if the second term of the left-hand side of (42) is small enough.…”

“…The corresponding value of 0  is substituted into (33), then 1  is found, etc. After the first iteration the solution is as follows:…”