  Photoinduced birefringence and diffraction efficiency in azo dye doped or grafted polymers: theory versus experiment of the temperature influenceBlanche, Pierre-Alexandre  ; ; et alin Journal of the Optical Society of America. B, Optical Physics (2000), 17(5), 729-740 We have investigated the influence of the temperature on the photoinduced birefringence as well as on the diffraction efficiency of azo dye doped or grafted polymers. The samples are composed of three ... [more ▼] We have investigated the influence of the temperature on the photoinduced birefringence as well as on the diffraction efficiency of azo dye doped or grafted polymers. The samples are composed of three polymer matrices containing 2, 5-dimethyl-4-(p-nitrophenylazo anisole). We propose two theoretical models to explain the experimental increase of both phenomena when the temperature is decreased. Models are based on the statistical angular distribution of the chromophores that depends on the intensity of the polarized laser beam in the media, counteracted by the thermal agitation. Parameters introduced in both models can be used to characterize the polymeric system properties. [less ▲] Detailed reference viewed: 14 (3 ULg) Ne VI spectrum; Bastin, Thierry ; Biémont, Emile et alin Journal of the Optical Society of America. B, Optical Physics (1999), 16 On the basis of all the available observations of the Ne VI spectrum, particularly the new beam-foil spectra obtained at Liège University, approximately 50 new line assignments are proposed and ... [more ▼] On the basis of all the available observations of the Ne VI spectrum, particularly the new beam-foil spectra obtained at Liège University, approximately 50 new line assignments are proposed and approximately 30 new energy levels are determined in Ne VI. All known energy levels have been improved, and a new value is proposed for the ionization potential. The new line identifications are supported by Hartree–Fock calculations combined with parametric fitting of energies and transition rates. [less ▲] Detailed reference viewed: 21 (4 ULg)Spectroscopy of Ne IV in the wavelength Range 450–1100 ÅBastin, Thierry ; Biémont, Emile ; Dumont, Paul-Dominique et alin Journal of the Optical Society of America. B, Optical Physics (1997), 14 An analysis of the Ne IV spectrum was undertaken in the 450–1100-Å spectral range. The spectra were produced by the beam–foil method with beam energies of 1.2 and 2.5 MeV, respectively. The resolution ... [more ▼] An analysis of the Ne IV spectrum was undertaken in the 450–1100-Å spectral range. The spectra were produced by the beam–foil method with beam energies of 1.2 and 2.5 MeV, respectively. The resolution that was achieved, with a normal-incidence 2-m spectrometer, was sufficient to identify 53 new Ne IV lines and, consequently, to determine 18 new levels in the quartet and doublet systems and one sextet term. The energy values of 13 additional levels were also revised. The classification work was facilitated by the use of scaled relativistic Hartree–Fock calculations. [less ▲] Detailed reference viewed: 16 (4 ULg) |
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