Alkali Halides
Mostrando 1-10 de 10 artigos, teses e dissertações.
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1. O plÃsmon da regiÃo de recobrimento da ligaÃÃo quÃmica como ferramenta para caracterizaÃÃo de materiais
Important issues can be raised about the possibility of relations between macroscopic properties of materials and concepts, introduced recently, of the chemical bond overlap polarizability (PR) and the concept of ionic specific valence (VIE). A proposal in which the overlap region of chemical bond is considered as a âplasmon‐likeâ charge distribution
Publicado em: 2009
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2. DÉSORPTION IONIQUE INDUITE PAR LASER EN INSULINE, CARBONE ET HALOGÉNURES ALCALINS / DESSORÇÃO INDUZIDA POR LASER EM INSULINA, CARBONO E HALETOS ALCALINOS / LASER INDUCED DESORPTION IN INSULIN, CARBON AND ALKALI HALIDES
O fenômeno de dessorção iônica a partir da incidência de pulsos de radiação laser ultravioleta sobre superfícies em vácuo foi estudada. A dessorção de três tipos diferentes de sólidos foi analisada: insulina, carbono (amorfo e grafite) e policristais de haletos alcalinos. Os processos fundamentais da interação da radiação laser com sólido e
Publicado em: 2006
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3. Medidas de tempos de relaxação spin-rede em cristais mistos de halogenetos alcalinos. / Spin-lattice relaxation measurements on mixed crystals of alkali halides.
Using magneto-optic techniques we have studied the ground state spin- lattice relaxation times (T1) of Fcenters in mixed Alkali Halide cristals (KCl-KBr). We describe a computer assisted system to optically measure short relaxation times (~1mS). The technique is based on the measurement of the Magnetic Circular Dicroism (MCD) presented by F centers. We obtai
Publicado em: 1983
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4. Estudos de condutividade elétrica em compostos iônicos do tipo ABF2 e A2BF6. / Study of electrical conductivity of ABF2 and A2BF6 ionic compounds.
The D.C. electrical conductivity technique has been used to determine the electrical conductivity values of several ionic compounds of the ABF6 family (A=Li, Na, K, Ag; B = P, Sb, Ti). Al1 these compounds have electrical conductivity values higher than those of alkali halides, however none of then can be classified as superionic conductors. Of the several io
Publicado em: 1980
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5. Comportamento de íons fora de centro em halogenetos alcalinos / Behaviour of off-center ions in alkali halides
Experimental results are given on the off-center behavior of Cu+ ion in RbCl, RbBr, Hbl, NaI and in mixed crystals of KI+%KCl and KCl+%KI, as also on Ag+ in RbI. We use UV optical absorption, ionic thermal current (ITC) and uniaxial stress induced dichroism techniques. It is studied the temperature dependence of the oscillator strength, the relaxation time a
Publicado em: 1978
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6. Medidas magneto-óticas de tempos de relaxação Spin-Rede em KBr e nos halogenetos de Na e Cs e estudo de Dicroismo Circular Magnético do Ion Co++ em KCl. / Magneto-optical measurements of spin-lattice relaxation times in KBr, Na and Cs halides and Magnetic Circular Dichroism of Co++ dopped KCl.
In this work we describe a Magnetic Circular Dicroism Spectrometer wich was used in the following experiments: 1) We measured the spin-lattice relaxation time (T1) for F centers in NaCl, NaBr, CsBr and CsCl, at 1,8°K in magnetic fields up to 15000Gs. We verified the suitability of the theory of ref.(O8) to explain the differences observed for halides of
Publicado em: 1977
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7. Study on Cu+ off- center dipoles in potassium halides / Estudos sobre dipolos fora de centro de Ions de CU+ em halogenetos alcalinos.
Theoretical and experimental investigations have concluded that Cu+ occupies an off-canter position in several alkali halides. In this work we report results obtained by ionic thermal-currents technique (ITC) to verify the electric dipole properties due to Cu+ ions in off-center position in KC1 crystals. This was developed to study the Cu+ ion behaviour in K
Publicado em: 1973
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8. Paired ions: Dipolar pairs as subset of diffusion pairs
Previous models for which theories of electrolytic conductance have been developed are reviewed. Discrepancies between theoretically derived values of parameters and parameters characteristic of real physical systems suggested the following revised model. Ions are counted as diffusion pairs if their center-to-center distance r is in the range a ≤ r ≤ R,
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9. Conductimetric determination of thermodynamic pairing constants for symmetrical electrolytes
Earlier theories of electrolytic conductance are reviewed; all of these, with the exception of the Arrhenius-Ostwald theory, are based on physical models. Their theory failed to describe the conductance of strong electrolytes because it did not include the effects (then unsuspected) of long-range forces on mobility. Thermodynamic derivations are independent
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10. Factor VIII Recombination After Dissociation by CaCl2
Factor VIII is a large protein molecule of molecular weight 2,000,000 or larger that elutes in the void volume on agarose gel chromatography. It has been shown previously that high concentrations of alkali halides and, more specifically, 0.25 M Ca2+ dissociate the molecule into a large carrier protein and a small fragment that retains the factor VIII activit