Valence Transition
Mostrando 1-12 de 34 artigos, teses e dissertações.
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1. O CONCEITO DE VALÊNCIA EM LIVROS DIDÁTICOS DE QUÍMICA GERAL ENTRE AS DÉCADAS DE 1890 E 1940
This paper aims to investigate the presentation of the concept of valence in college-level, general chemistry textbooks published in the USA between the 1890s and the 1940s. The delimited period covers the emergence of theories about atomic structure, electronic distribution and chemical bonding. Transition from the classical concept of valence (as the combi
Quím. Nova. Publicado em: 2019-02
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2. Band Structure, Charge Distribution and Optical Properties of AlPxSb1-x Ternary Semiconductor Alloys
The present contribution studies on the composition dependence of the electronic and optical properties of the zinc-blende alloy system AlPxSb1-x. The calculations are performed using a pseudopotential approach under the virtual crystal approximation. Features such as electronic band structure, energy band-gaps, refractive index, dielectric constants and val
Mat. Res.. Publicado em: 21/05/2018
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3. ESTRATÉGIAS E MATERIAIS UTILIZADOS EM FOTOCATÁLISE HETEROGÊNEA PARA GERAÇÃO DE HIDROGÊNIO ATRAVÉS DA FOTÓLISE DA ÁGUA
Among the various technologies for the production of hydrogen fuel, heterogeneous photocatalysis is one of the most promising, especially with the use of semiconductors, notably TiO2. However, the use of TiO2 is limited by hindrances for the photolysis of water, such as wide bandgap, a less negative conduction band reduction potential as compared to that of
Quím. Nova. Publicado em: 2017-06
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4. Investigation of structural, electronic and magnetica properties of Ca2-xLaxFelrO6, Sr2-xLaxFelrO6 e TbMnO3 oxides / Investigação as propriedades estruturais, eletronicas e magneticas dos oxidos Ca2-xLaxFelrO6, Sr2-xLaxFelrO6 e TbMnO3
For many decades the transition metal oxides are subject of great scientific interest because of the wide variety of interesting physical properties and their potential technological applications. More recently, for example, oxides of transition metals with multiferroic properties have been considered as potential magneto-electronic devices. Many transition
Publicado em: 2010
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5. Caracterização estrutural, morfológica e magnética da dupla perovsquita Ca2MnReO6
Compounds with structure of ordered double perovskyte, A2BBO6 (A being an alkalineearth and B being a transition-metal in alternate sites) have attracted interest of the researches because their strong correlated structural and magnetic properties. Moreover, they are suitable candidates to produce devices with great application in spin-electronic, named spin
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 25/06/2009
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6. Estudo das transiÃÃes de fase do RbBi0,31 3Nd0,02 W8/3O9, submetido a variaÃÃes de pressÃo hidrostÃtica e temperatura. / Studies of phase transitions of RbBi0,313Nd0,02W8/3O9 submit variation of hydrostatic pressure en temperature
Tungsten bronzes has attracted great attention owing to it is interesting physical properties. Hexagonal tungsten of the form AxWO3 (with A = K, Rb, Cs), are well know superconductors. The RbBi1/3W8/3O9 (RBW) material, belongs to the valence balanced hexagonal tungsten materials with ABxW3-xO9 stoichiometry (with A = Cs, K, Rb, Tl, and B = Bi, Nd, Ta, Zr, Sc
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 16/02/2009
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7. Fotoionização de atomos relativisticos / Photoionization of relativistic atoms
In this work we present photoionization results for the valence s-electrons of Sodium, Potassium, Rubidium and Cesium atoms including relativistic effects. In our calculations we consider the photoionization of a non-polarized atom by linearly polarized light, using half occupation transition states, within the electric dipole approximation and the Local Den
Publicado em: 2007
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8. PRESSURE-TEMPERATURE-COMPOSITION PHASE DIAGRAM OF THE HEAVY FERMION COMPOUND CE2RH(1−X)IR(X)IN8 / DIAGRAMA DE FASES PRESSÃO-COMPOSIÇÃO-TEMPERATURA DO COMPOSTO FÉRMION PESADO CE2RH(1−X)IR(X)IN8
Heavy fermion compounds behave differently from typical metals at low temperatures, where the phenomena that arise due to the correlation between conduction electrons and the f ions of the lattice become evident. An increased effective electronic mass that can reach values as high as hundreds of times the free electron mass and the coexistence of magnetic or
Publicado em: 2006
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9. Estruturas de barreira dupla de PbTe/PbEuTe crescidas por epitaxia de feixe molecular / PbTe/PbEuTe double barrier structures grown by molecular beam epitaxy
This work reports the growth of PbTe/Pb(1-x)Eu(x)Te double barrier (DB) structures by molecular beam epitaxial and the device processing aiming the resonant tunneling measurement. The samples were grown on (111) BaF(2) substrates at 300°C. Resistivity and Hall effect measurements were performed on reference films to determine the most suitable electrical pr
Publicado em: 2006
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10. Theoretical investigations on valence vibronic transitions
This article reviews previously employed methods to study several valence electronic transitions, optically forbidden or not, enhancing intensity through vibronic coupling. Electronic transition dipole moments were calculated using several ab initio methods including electron correlation. In this method the square of the electronic transition dipole moments
Brazilian Journal of Physics. Publicado em: 2005-12
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11. PHYSICS OF STRONGLY CORRELATED AND DISORDERED SYSTEMS / FÍSICA DE SISTEMAS FORTEMENTE CORRELACIONADOS E DESORDENADOS
In this thesis we study the properties of strongly correlated and disordered materials, using model Hamiltonians to describe them. The thesis is divided in two parts. The first one studies the periodic Anderson model used to describe the properties of a Kondo insulator. In particular we take Ce3Bi4Pt3 as a paradigmatic compound, characterized by a small gap(
Publicado em: 2004
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12. Um modelo molecular para o magnetismo em ferro, cobalto e nÃquel
The orbital angular moment and the angular moment of spin guarantee the magnetism of the substance. When treating, specifically, of the magnetism in the iron, cobalt and nickel we are admired for the complexity that these metals of transition present in its referring electronic distributions to its levels of valence. Literature registers that many electronic
Publicado em: 2003