Electronic Spin Resonance
Mostrando 13-24 de 26 artigos, teses e dissertações.
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13. Estudo das propriedades ópticas e estruturais de nanocristais de MnTe em vidros óxidos
Nanoestruturas baseadas em Semicondutores Magnéticos Diluídos (DMS), também denominado semicondutor semimagnético, tem despertado o interesse da comunidade científica devido as suas singulares propriedades magneto-ópticas e de transporte. Recentemente, foi estudada possibilidade de manipulação de um único spin em nanocristais DMS, tornando-os um pro
Publicado em: 2006
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14. ELECTRONIC CORRELATION IN QUANTUM DOTS SYSTEMS / CORRELAÇÃO ELETRÔNICA EM SISTEMAS DE PONTOS QUÂNTICOS
In this thesis we investigate the effects of the eletron- eletron interaction on the transport properties of nanosystems. In particular, we study systems constituted by two quantum dots conected to leads, in different topologies. Our main interest is to study the effects of the Kondo regime and the electronic phase on the conductance. In the configuration wh
Publicado em: 2004
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15. Novos desenvolvimentos e aplicaÃÃes de mÃtodos de quÃmica quÃntica para compostos de coordenaÃÃo com Ãons lantanÃdeos
Theoretical studies on lanthanide compounds were performed, and divided into three parts: (i) generalization of the Linderberg-Seamans equations for an s-p-d-f basis set; (ii) study of the ligand-to-lanthanide ion charge transfer transitions (LMCT) with the ZINDO98 program using the INDO/S semiempirical hamiltonian and (iii) a study of point charge and charg
Publicado em: 2003
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16. Propriedades magneticas de manganitas, fitas amorfas e filmes finos com anisotropia unidirecional
In this work we will present a study of the magnetic properties of three systems: manganites, amorphous ribbons and bilayers with exchange bias. Whole the magnetization measurements were made in a SQUID magnetometer developed during the period of this thesis. We studied several films and buck manganitas samples. All samples present the effect of the colossal
Publicado em: 2002
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17. Eletron Paramagnetic Resonance: theory of experiments. Electronic relaxation of the intersticial atomic hydrogen in CaF2: evidence of spectral diffusion / Ressonância Paramagnética Eletrônica: teoria da medida. Relaxação eletrônica do hidrogênio atômico intersticial em CaF2 : evidência da difusão espectral.
Na primeira parte deste trabalho, são discutidos alguns fatores que determinam a forma correta de operação de um espectro convencional de RPE. Um sistema específico, possuindo o circuito usual de "ponte de microonda", é analisado e as condições ideais para a realização da medida das duas componentes da susceptibilidade magnética complexa são deter
Publicado em: 1979
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18. Electronic properties of the casein-methylglyoxal complex.
Measurements of the electron spin resonance, direct current conductivity, microwave permittivity, and electronic transference number are reported for the brown casein-methylglyoxal complex. Compared with normal white casein, the colored casein complex exhibits an increased electronic activity. This is considered to arise from the electron-accepting action of
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19. Synthesis and characterization of "face-to-face" porphyrins.
The syntheses of four binary porphyrins, two of which are constrained to a "face-to-face" conformation, and their Co2+ and Cu2+ derivatives are described. Electron spin resonance indicates that the intermetallic separation in the binuclear "face-to-face" porphyrins is about 6.5-6.8 A. Electronic spectra and proton magnetic resonance spectra support the postu
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20. Relationship between the oxidation potential and electron spin density of the primary electron donor in reaction centers from Rhodobacter sphaeroides
The primary electron donor in bacterial reaction centers is a dimer of bacteriochlorophyll a molecules, labeled L or M based on their proximity to the symmetry-related protein subunits. The electronic structure of the bacteriochlorophyll dimer was probed by introducing small systematic variations in the bacteriochlorophyll–protein interactions by a series
The National Academy of Sciences of the USA.
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21. Nitric oxide binding at the mononuclear active site of reduced Pyrococcus furiosus superoxide reductase
Nitric oxide (NO) has been used as a substrate analog to explore the structural and electronic determinants of enzymatic superoxide reduction at the mononuclear iron active site of Pyrococcus furiosus superoxide reductase (SOR) through the use of EPR, resonance Raman, Fourier transform IR, UV-visible absorption, and variable-temperature variable-field magnet
The National Academy of Sciences.
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22. Optical Versus Thermal Transitions in Solids at High Pressure
Pressure-induced electronic transitions have been observed in a wide variety of materials. In particular, Mössbauer resonance studies under high pressure have revealed changes of oxidation state and spin state of iron as a function of pressure. These processes involve the thermal transfer of an electron to a new ground state of the system. The difference in
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23. Ligated chlorophyll cation radicals: Their function in photosystem II of plant photosynthesis
Magnesium tetraphenylchlorin, a synthetic model for chlorophyll, exhibits significant variations in the unpaired spin densities of its cation radicals with concomitant changes in oxidation potentials as a function of solvent and axial ligand. Similar effects are observed for chlorophyll (Chl) a and its cation radicals. Oxidation potentials for Chl → Chl+.
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24. Chromophore organization in photosynthetic reaction centers: High-resolution magnetophotoselection
The electron spin resonance spectrum of the triplet excited state of Rhodopseudomonas spheroides R-26 reaction centers has been studied after excitation with the polarized narrow-bandwidth output of a tunable dye laser from 520 to 670 nm. A theory is developed relating experimental observables to the angles between the electronic transition dipole moment of