Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Hyperfine broad distribution

The variations observed in the spectra with changing water content (figure 4) imply a modification of the environment of the ferrous ion below 6 % water. [Fe(H20)6]2+ complexes are progressively dehydrated, but it is difficult to establish a precise, quantitative correlation between the hyperfine parameters and the number of water molecules in the vicinity of the ion. The influence of the structure of the Nafion itself becomes increasingly felt as the water concentration decreases, and certainly leads to a very broad distribution of environments for the ferrous ion, as may be seen from the variation in linewidth as the water content approaches zero. [Pg.179]

It is obvious that the high degree of structural disorder in such a poorly crystalline system causes broad distributions of hyperfine parameters resulting in broad-lined doublets and sextets. At RT a broad doublet is obtained (Fig. 3.7) with average A in the range 0.7-0.9 mm/s. Though the spectra reflect in fact a broad... [Pg.107]

All hyperfine parameters of the atoms near the surface can be different fi-om the hyperfine parameters of the atoms in the interior. In general, however, surface and bulk contributions are not clearly differentiated from each other. Because of the great variety of surface sites, the hyperfine parameters of the surface atoms, especially the hyperfine field, can be broadly distributed. These distributions combine with the effects of the distributions of particle size and shape, often making surface and volume effects difficult to distinguish from one another. Investigations based on the isotope selectivity of Mossbauer spectroscopy may then be particularly useful. [Pg.401]

The Mossbauer spectra of NpSe below at 38 K exhibit a fairly broad distribution of hyperfine fields pointing towards an incommensurate spin structure. The field distribution clearly changes shape with temperature meaning that details of the spin modulation are also temperature dependent. The spectral shape near indicates a first-order phase transition. A positive determination of spin structure by neutron diffraction is still outstanding (Blaise et al. 1992). At low temperatures type-II multi-fe order seems to be indicated, but this does not explain the distribution in hyperfine fields which still prevails at 4.2 K in the Mossbauer spectrum. [Pg.606]

Eu was implanted into a stainless steel foil ( Fe62Ni2 yCriK) at 400 keV and doses of (a) 1.2 x lO cm- and (b) 6 x 10 /cm-. respectively. Analysis of the Mossbaucr spectra for dose (a) led to the as.sumption of four phases the stainless steel matrix, a martensitic phase with a broad hyperfine field distribution, a magnetic phase with a well-defined hyperfine field of. 33.6 T and an oxide phase similar to FeO. Since a set of 10 Mossbaucr spectra was recorded at dif-... [Pg.362]

Spectrum simulation treated the hyperfine interactions by second order perturbation theory and there were distributions in D and E/D, because strain in these parameters dominated the spectra. Spectral features grow in up to 1 equivalent of added Mn(II) at geff = 15.4, 5.3, 3.0 and 2.0 (Bi 1B) and a broad signal with a... [Pg.387]

According to one s prejudices this spectrum can be analysed into two, characteristic of two different radicals, or treated as if it were the property of one radical having a hyperfine coupling of 11 G and a set of nine lines alternately narrow and broad but with a binomial distribution of intensities for both narrow and broad sets. [Pg.341]


See other pages where Hyperfine broad distribution is mentioned: [Pg.419]    [Pg.419]    [Pg.2832]    [Pg.105]    [Pg.270]    [Pg.676]    [Pg.2831]    [Pg.272]    [Pg.386]    [Pg.379]    [Pg.223]    [Pg.255]    [Pg.404]    [Pg.410]    [Pg.423]    [Pg.427]    [Pg.606]    [Pg.606]    [Pg.613]    [Pg.618]    [Pg.368]    [Pg.156]    [Pg.14]    [Pg.24]    [Pg.73]    [Pg.183]    [Pg.156]    [Pg.337]    [Pg.2823]    [Pg.6536]    [Pg.2822]    [Pg.6217]    [Pg.6535]    [Pg.670]    [Pg.138]    [Pg.521]    [Pg.125]    [Pg.423]    [Pg.194]    [Pg.393]    [Pg.770]    [Pg.539]    [Pg.363]    [Pg.377]   
See also in sourсe #XX -- [ Pg.606 ]




SEARCH



Broad

Broadness

© 2024 chempedia.info