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On the Relation Between Conformational Changes and Optical Properties in Oligothiophenes, 2. Linear and Nonlinear Optical Properties
Author(s) -
Lukeš Vladimír,
Breza Martin,
Pálszegi Tibor,
Laurinc Viliam,
Vrábel Imrich
Publication year - 2001
Publication title -
macromolecular theory and simulations
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.37
H-Index - 56
eISSN - 1521-3919
pISSN - 1022-1344
DOI - 10.1002/1521-3919(20010701)10:6<592::aid-mats592>3.0.co;2-4
Subject(s) - hyperpolarizability , maxima and minima , planar , chemistry , molecular physics , perpendicular , maxima , nonlinear optics , nonlinear optical , resonance (particle physics) , orientation (vector space) , condensed matter physics , ring (chemistry) , nonlinear system , physics , atomic physics , quantum mechanics , geometry , mathematics , mathematical analysis , organic chemistry , art , computer graphics (images) , performance art , computer science , art history
The dependence of microscopic electronic non‐resonant polarizabilities ( α ) and second‐order hyperpolarizabilities ( γ ) of short oligothiophenes on the mutual torsional ring orientation was investigated by employing the time‐dependent Hartree–Fock method within the AM1 approximation. The α and γ quantities exhibit the uniform shape of the torsional dependence regardless of the mutual rings' orientations for all the systems under study (minima occur for perpendicular geometries and maxima are indicated for planar structures). The frequency dependence of γ hyperpolarizability below the first resonance frequency is fairly well evaluated in the form of a simple power series. The trends of AM1 results agree with the current theoretical treatments as well as experimental data.