title: Specific features of UV-vis absorption spectra of cis- and trans-polythiophenes.
abstract: UV-vis optical spectra of several polythiophene with number of dimers n=1, 5, 10, 15 for cis- and trans-forms were investigated. The study was done theoretically using semi-empirical AM1 (Austin Model 1) and PM3 (Parametric Method 3) methods with the appropriate molecular geometry optimization. The experimental UV-vis absorption spectra were used for verification of the both semi-empirical theoretical models. With the increasing number of dimers a red shift of the absorption edge was observed. Solvent does not play a crucial role on behavior of the absorption spectrum. A comparison of the both semi-empirical methods with the observed experimental absorption spectra is performed. Role of state dipole moments of the investigated polythiophenes in the behavior of the observed UV-vis spectra is discussed. Particular role of pi-conjugated bonds is demonstrated.
authors.affiliation: Solid State Department, Institute of Physics, J. Długosz University of Czestochowa, Al. Armii Krajowej 13/15, PL42201 Czestochowa, Poland.
authors.forename: I
authors.initials: I
authors.lastname: Fuks-Janczarek
authors.forename: I V
authors.initials: IV
authors.lastname: Kityk
authors.forename: R
authors.initials: R
authors.lastname: Miedziński
authors.forename: E
authors.initials: E
authors.lastname: Gondek
authors.forename: A
authors.initials: A
authors.lastname: Danel
authors.forename: M
authors.initials: M
authors.lastname: Zagorska
mesh_terms: D007536:Isomerism; D015394:Molecular Structure; D011108:Polymers / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013876:Thiophenes / Q000737:chemistry*
chemical_list: D011108:Polymers; D013876:Thiophenes; C066730:polythiophene