Crystal Field Theory
Mostrando 1-12 de 23 artigos, teses e dissertações.
-
1. CONTRIBUIÇÃO AO ESTUDO DE CAMPO CRISTALINO E TRANSIÇÕES 4f-4f EM SISTEMAS CONTENDO LANTANÍDEOS. / CONTRIBUTION TO THE STUDY OF CRYSTAL AND FIELD 4F-4F TRANSITIONS IN SYSTEMS CONTAINING LANTHANIDES.
A theoretical study of the interactions between the 4f electrons in lanthanide ions (Ln3 +) with the chemical environment was made using crystal field theory. The main effects were studied: change in position of the berycentre of the energy levels of the free ion, maximum splitting of the J level and contribution to 5D0-7F0 transition of Eu3+ ion. Use of sec
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 18/09/2012
-
2. Fases magnéticas de sistemas nanoestruturados de terras-raras
There is presently a worldwide interest in artificial magnetic systems which guide research activities in universities and companies. Thin films and multilayers have a central role, revealing new magnetic phases which often lead to breakthroughs and new technology standards, never thought otherwise. Surface and confinement effects cause large impact in the m
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 04/02/2011
-
3. Líquidos nemáticos e relatividade geral
In the mean 80´s, it was proposed that the rheologic properties of liquidcrystal could be obtained through affine transformation, in which the interaction potential of aspheric molecule is deformed to assume the ellipsoidal shape of potential liquid crystal´smolecular interaction. When this procedure is done point to point, the usuals derivatives donot get
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 27/07/2010
-
4. Spectroscopies of photoluminescence and excitation of MgGa2O4 samples doped with Mn2+. / Espectroscopia de fotoluminescência e excitação de amostras MgGa2O4 dopadas com Mn2+
This work presents the room temperature photoluminescence and excitation spectroscopes data of MgGa2O4 samples doped with 0.5% and 10.0% Mn2+. The polycrystalline samples were produced by solid-state reaction at high temperature and characterized with X ray Diffraction and SEM. The photoluminescence spectra showed emission at green and red spectral regions,
Publicado em: 2009
-
5. Estudo da desativação do agente VX usando o MgO por cálculos ab initio
The organophosphates are used in industry, in the fields of dyes, varnishes, artificial leather, electrical insulation, waterproofing, plastics, oil additives and solvents, are also used in medicine to treat diseases such as glaucoma, in the household and in agriculture are applied as insecticides and pesticides. Besides these various civilian facilities, th
Publicado em: 2009
-
6. Phase diagrams of the Blume-Emery-Griffiths thin films
We study the spin-1 Blume-Emery-Griffiths model with bilinear and biquadratic exchange interactions and single-ion crystal field, using the mean field theory. In addition to the four usual phases: The disordered phase D, the ferromagnetic phase F, the staggered quadrupolar phase SQ and The ferrimagnetic phase I, we found two new phases, in the case of a thin
Brazilian Journal of Physics. Publicado em: 2006-06
-
7. Estudo das propriedades magneticas de novos compostos intermetalicos de terras raras / Magnetic properties of a new series of rare-earth based intermetallic
Primeiramente sintetizados por Remeika et al., para M = Rh, em 1980, os compostos intermetálicos ternários do tipo R3M4S n13, onde R = íon de terra rara e M = metal de transição (por exemplo, Rh, Ir e Co), cristalizam-se em uma estrutura cúbica. Apesar de possuírem uma estrutura cristalina relativamente simples, esses sistemas apresentam uma série de
Publicado em: 2006
-
8. Espectros eletrônicos de alguns complexos de geometria octaédrica de Ni2+: uma introdução prática à teoria do campo cristalino no curso de graduação
The experiment introduces the undergraduate students to the crystal field theory. The electronic spectra of the octahedral complexes of [Ni(L)n]2+ (L = H2O, dmso, NH3 and en) obtained in the experiment are used to calculate 10Dq and B parameters. The experiment shows how the parameters can be calculated and correlated with the nature of the ligands and the f
Química Nova. Publicado em: 2005-02
-
9. Propriedades de termoluminescência, ressonância paramagnética eletrônica e absorção óptica da rodonita natural e sintética / Thermoluminescence, electron paramagnetic resonance and optical absorption properties of natural and synthetic Rodonita
The optical absorption, electron paramagnetic resonance and thermoluminescence properties of natural silicate mineral, rhodonite with chemical formula (Mn,Ca,Fe,Mg)SiO3 as well as synthetic samples pure or doped have been investigated. Synthetic samples were obtained heating appropriated mixture of oxides components of rhodonite to above melting temperature
Publicado em: 2005
-
10. PROPRIEDADES TÉRMICAS E MAGNÉTICAS DOS BOROCARBETOS / THERMAL AND MAGNETIC PROPERTIES OF A SERIES OF BOROCARBIDES
We propose a spin hamiltonian to describe the magnetic and thermal properties of a series of borocarbides. The effect of the crystal electric field is simulated by an effective magnetic field. By applying spin wave theory we have found the dispersion relation and the density of state for the magnos as well. In presence of an external magnetic field this dens
Publicado em: 2002
-
11. Comportamento de vortices em cupratos supercondutores e transição tipo supercondutor-isolante em grafite
In this thesis we have studied dynamics and pinning properties of the vortex matter in high temperature superconductors. It is found that the second magnetization peak (SMP) effect, an increase in the magnetization hysteresis loop width in Bi2212 single crystals vanishes with decreasing the crystal size. We showed that this effect is not related to the criti
Publicado em: 2002
-
12. VORTEX STATES IN UNCONVENTIONAL SUPERCONDUCTORS / ESTADOS DE VORTICES EM SUPERCONDUTORES NAO-CONVENCIONAIS
The theory of Bardeen, Cooper and Schrieffer (BCS) had great success in explaining most properties of superconducting materials. These materials, where BCS applies, are denominated conventional superconductors. the experimental evidence of unconventional superconductivity in several materials reopened discussions about the phenomenon. While, in conventional
Publicado em: 2002