title: Determination of orientation distribution function of anisotropic paramagnetic species by analysis of ESR spectra angular dependence.
abstract: A method has been developed to determine orientation distribution function (ODF) of anisotropic paramagnetic species by analysis of the angular dependence of the ESR spectra. The method is based on computational spectra simulation. The ODF is represented as an expansion in terms of orthonormal functions. The expansion coefficients are determined through minimization of discrepancies between simulated spectra and experimental ones. By means of the suggested method we have determined the orientation distribution functions for radical probe 2,2,6,6-tetramethyl-4-ol-piperidinooxyl in 4-n-amyl-4'-cyanobiphenyl aligned by magnetic field and 2-septadecyl-2,3,4,5,5-pentamethylimidazolidine in polyethylene stretched films. In each case, thermal evolution of the ODF has been investigated.
authors.affiliation: Department of Chemistry, M.V. Lomonosov Moscow State University, Vorobievy Gory, 119899 Moscow, Russia. vorobiev@excite.chem.msu.ru
authors.forename: Andrey Kh
authors.initials: AKh
authors.lastname: Vorobiev
authors.forename: Natalia A
authors.initials: NA
authors.lastname: Chumakova
mesh_terms: D000465:Algorithms; D016880:Anisotropy; D003198:Computer Simulation; D003497:Cyclic N-Oxides / Q000032:analysis*; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D048289:Imidazolidines / Q000032:analysis*; D008956:Models, Chemical; D015233:Models, Statistical; D015336:Molecular Probe Techniques; D009716:Numerical Analysis, Computer-Assisted; D012984:Software; D013113:Spin Labels; D016008:Statistical Distributions
chemical_list: D003497:Cyclic N-Oxides; D048289:Imidazolidines; D013113:Spin Labels; C001803:tempol