کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5418139 1506977 2007 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Symmetry breaking in cationic and anionic polymethine dyes
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
Symmetry breaking in cationic and anionic polymethine dyes
چکیده انگلیسی

The electron density distribution and equilibrium molecular geometry of ionic polymethine dyes containing both the simplest terminal groups and carbo and heterocyclic residues were investigated by ab initio and AM1 methods. It is shown that charge waves and wave of the carbon-carbon bond lengths in the conjugated chain are of solitonic nature. The dimensions of the charge (electron or hole) soliton and geometrical (topological) soliton are practically unsensitive to the chain lengths, while the wave shape depends on the donor/acceptor strength of the terminal groups. If the length of the chromophore exceeds the dimension of the solitons, then the soliton center in the substituted ionic conjugated systems shifted to one of the chain ends, what leads to an appearance of the asymmetrical form. The conditions of this symmetry breaking (crucial number of the vinylene groups in the chain, effective length and donor/acceptor strength of the terminal residues, total charge) was found and was established that no moving of the solitons occurs in the unsubstituted conjugated ions.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Structure: THEOCHEM - Volume 802, Issues 1–3, 8 January 2007, Pages 75-83
نویسندگان
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