Relationship between the infrared absorption spectra and crystal structure of the hydroxides of the rare earth elements and yttrium

1967 ◽  
Vol 8 (2) ◽  
pp. 229-233 ◽  
Author(s):  
P. V. Klevtsov ◽  
R. F. Klevtsova ◽  
L. P. Sheina
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Absorption Spectra ◽  
Infrared Absorption ◽  
Infrared Absorption Spectra ◽  
The Rare Earth

Infrared absorption spectra of formates of the rare earth elements

1967 ◽  
Vol 8 (1) ◽  
pp. 45-49 ◽  
Author(s):  
O. D. Saralidze ◽  
L. P. Shklover ◽  
K. I. Petrov ◽  
V. E. Plyushchev
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Absorption Spectra ◽  
Infrared Absorption ◽  
Infrared Absorption Spectra ◽  
The Rare Earth

A refinement of the dickite structure and some remarks on polymorphism in kaolin minerals

1961 ◽  
Vol 32 (252) ◽  
pp. 683-704 ◽  
Author(s):  
Robert E. Newnham
Keyword(s):  
Crystal Structure ◽  
Absorption Spectra ◽  
Infrared Absorption ◽  
Structural Features ◽  
Mirror Image ◽  
Hydrogen Atoms ◽  
Octahedral Layer ◽  
Layer Structures ◽  
Infrared Absorption Spectra ◽  
Interlayer Bonding

SummaryThe crystal structure of the clay mineral dickite (Al2Si2H4O9) has been refined to a greater accuracy than that reported in an earlier analysis. Improved lattiçe parameters are: a 5·15±0·001, b 8·940±0·001, c 14·424 ± 0·002Å., β 96° 44′± 1′. The dickite structure shows several significant distortions from the geometry of the idealized kaolin layer, including deformation and rotation of the silica tetra-hedra. The most striking features of the octahedral layer are the extremely short shared edges of 2·37 Å. Although the analysis was not sufficiently accurate to position the hydrogen atoms with certainty, a model consistent with the infrared absorption spectra is proposed. The stacking sequences of kaolin-layer minerals have been considered with reference to the structural features observed in dickite. There are thirty-six ways of superposing two kaolin layers commensurate with the OH-O bonds found in kaolinite, dickite, and nacrite. The twelve sequences showing the least amount of cation-cation superposition between consecutive kaolin layers can be used to construct two one-layer cells, kaolinite and its mirror image, and twelve two-layer cells, including dickite and nacrite. The distortions of the kaolin layer introduce secondary variations in the interlayer bonding that suggest that dickite and nacrite are the most stable of the kaolin layer structures, since they possess the shortest oxygen-hydroxyl contacts.

The Influence of Sample Self-Absorption on Wavelength Shifts and Shape Changes in the Soft X-Ray Region: The Rare-Earth M Series

1967 ◽  
Vol 11 ◽  
pp. 230-240
Author(s):  
David W. Fischer ◽  
William L. Baun
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Absorption Spectra ◽  
Emission Spectra ◽  
Emission Lines ◽  
Electron Transitions ◽  
Emission And Absorption Spectra ◽  
Real Emission ◽  
Shape Changes ◽  
The Rare Earth

AbstractThe Mα and Mβ emission spectra and the Mjv and My absorption spectra have been studied for the entire series of rare-earth elements. It is conclusively shown that the complicated multiplet structure observed in the emission spectra is not real emission structure but is, instead, produced by sample self-absorption. This is demonstrated by observing the emission spectra over wide variations in take-off angle and bombarding electron energies and finally by comparing the detailed structure of both the emission and absorption spectra. The MIV and MV absorption structure completely overlaps the Mα and Mβ emission lines, which are each found to have but one intensity maximum when obtained under conditions of minimum. self-absorption. Some of these spectra have never been shown previously, while others have been studied in detail by several investigators. Points of agreement and disagreement with previous work are mentioned, and the wavelengths of the emission lines and absorption edges are listed for all of the rare-earth elements. It is concluded that the 4f → 3d electron transitions are reversible in these elements.

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