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Collisional-electron detachment of Cl/sup -/ on diatomic molecules

Description: Recent experimental results for collisional-electron detachment of Cl/sup -/ by H/sub 2//D/sub 2/, N/sub 2/, O/sub 2/, NO, and CO are discussed. The emphasis is on angular distributions and energy loss measurements for laboratory energies of a few hundred eV. Evidence for the possibility of bound excited states of N/sub 2/Cl and COCl and the role of target negative-ion resonant states is presented.
Date: January 1, 1981
Creator: Annis, B.K. & Datz, S.
Partner: UNT Libraries Government Documents Department

Neutron scattering from solutions: the hydration of lanthanide and actinide ions

Description: The neutron scattering difference method is described and applied to investigations of the aqua rare-earth ions, Nd/sup 3 +/ and Dy/sup 3 +/. Metal-water distances and hydration numbers have been unambiguously determined for these ions' inner coordination spheres. The values of the hydration number, n, of 8.5 +- 0.2 for Nd/sup 3 +/ and 7.4 +- 0.5 for Dy/sup 3 +/, directly support the claim of Spedding et al. that n decreases by one unit across the lanthanide series. The possible application of this method to actinide ions in solution is also discussed. 7 refs., 4 figs.
Date: January 1, 1985
Creator: Hahn, R.L.; Narten, A.H. & Annis, B.K.
Partner: UNT Libraries Government Documents Department

The characterization of fluorinated graphite

Description: The characterization of solid fossil fuels by chemical and spectroscopic methods requires extensive modelling in less complex systems for chemical proof of principle and technique development. In previous work coal was fluorinated with dilute, elemental fluorine under conditions that were expected to lead to materials that contain only fluoromethine moieties. The solid state, cross polarization/magic angle spinning (CP/MAS) {sup 13}C NMR spectra of the fluorinated coal are complex, indicating more chemical modification than originally anticipated. Our goal in the coal derivatization was to sequentially increase the severity of the fluorination and observe by {sup 19}F and {sup 13}C NMR the type and concentration of fluorine functional groups created in the coal milieu. This requires the ability to discriminate between C, CF, CF{sub 2}, and CF, moieties in the coal matrix. The task can be accomplished by implementing the spectral editing technique of Wu and Zilm which distinguishes different kinds of carbon resonances, especially CH and CH{sub 2} resonances. These experiments utilize cross polarization (CP) and polarization inversion (PI) to effect the discrimination. Our version of this experiment is a triple resonance experiment that incorporates {sup 19}F-{sup 13}C CP, PI, and simultaneous {sup 1}H and {sup 19}F dipolar decoupling. In order to evaluate the elemental fluorine chemistry in a matrix simpler than coal, fluorinated graphite was prepared. X-ray photoelectron spectroscopy (XPS) was used to characterize the surface species, i.e., count CF, CF{sub 2} and CF{sub 3} species. These well-characterized samples are the models we will use to test the NIVIR editing experiments. The XPS and atomic force microscopy (AFM) data on the first fluorinated graphites we have prepared are reported in this paper.
Date: December 31, 1995
Creator: Hagaman, E.W.; Gakh, A.A. & Annis, B.K.
Partner: UNT Libraries Government Documents Department

Small angle neutron scattering (SANS) and small angle x-ray scattering (SAXS) analysis of polyaniline salts and blends

Description: Doped polyaniline emeraldine salts (PANI-ES) exhibit good environmental stability with a high level of conductivity (1 to 300 S/cm). However, they suffer from the fact that they have poor mechanical properties and must be blended with an insulating host polymer to be useful in industrial applications. Polyaniline blends are a new type of conducting material that typically show very low onsets of conductivity unlike that of metal filled blends. This is primarily due to the unique cellular geometry of the PANI-ES that is formed within the insulating host polymer. The formation of this immiscible polymer network may be due in part to structural and conformational differences in the blend components.
Date: June 1, 1996
Creator: Hopkins, A.R.; Rasmussen, P.G.; Basheer, R.A.; Annis, B.K. & Wignall, G.D.
Partner: UNT Libraries Government Documents Department

Role of dopant counter-anion functionality in polyaniline salts/blends and implications to morphology

Description: In this paper, wide and small angle X-ray scattering techniques (i.e., WAXS and SAXS) and light microscopy are used to characterize the influence of the dopant`s structure on the morphology of both polyaniline salt and blend. In an attempt to modify the morphology of the PANI-ES, the authors have evaluated a number of doping acids (i.e., methane sulfonic acid (HMSA), butane sulfonic acid (HBSA), dodecyl benzene sulfonic acid (HDBSA) and camphor sulfonic acid (HCSA)) that vary in size and polarity to better understand the role of the acid in PANI-ES`s morphology and the resulting electrical conductivity. These salts were solution blended with polycaprolactam using hexafluoro-2-propanol (HFIP) as a solvent. The other goal was to investigate the effect of the counter-anion structure on the nature of the phase separated PANI-ES network. The shape of the PANI-ES network in the host polycaprolactam has important implications on the nature of conduction behavior and the final electrical conductivity of the blend.
Date: March 1, 1997
Creator: Hopkins, A.R.; Rasmussen, P.G.; Basheer, R.A.; Annis, B.K. & Wignall, G.D.
Partner: UNT Libraries Government Documents Department

Role of dopant counter-anion functionality in polyaniline salts/blends and implications to morphology

Description: Polyanilines are of particular current interest primarily due to their relative ease of synthesis, low cost and stable conductivity in air. The insulating, polyaniline emeraldine base (PANI-EB) form becomes electrically conducting by preferential protonation or doping the imine nitrogen sites to yield an electrically conducting polyaniline emeraldine salt (PANI-ES). In this paper, wide and small angle X-ray scattering techniques (i.e., WAXS and SAXS) and light microscopy are used to characterize the influence of the dopant`s structure on the morphology of both polyaniline salt and blend. In an attempt to modify the morphology of the PANI-ES, the authors have evaluated a number of doping acids (i.e., methane sulfonic acid (HMSA), butane sulfonic acid (HBSA), dodecyl benzene sulfonic acid (HDBSA) and camphor sulfonic acid (HCSA)) that vary in size and polarity to better understanding the role of the acid in PANI-ES`s morphology and the resulting electrical conductivity. The other goal was to investigate the effect of the counter-anion structure on the nature of the phase separated PANI-ES network. The shape of the PANI-ES network in the host polycaprolactam has important implications on the nature of conduction behavior and the final electrical conductivity of the blend.
Date: April 1, 1997
Creator: Hopkins, A.R.; Rasmussen, P.G.; Basheer, R.A.; Annis, B.K. & Wignall, G.D.
Partner: UNT Libraries Government Documents Department