Lanthanide spectroscopy

Biinzli, J.-C.G and Eliseeva, S.V (2010) Basics of lanthanide photophysics, in Series on Fluorescence, Lanthanide Spectroscopy, Materials and Bio-Applications, Vol. 7 (eds P. Hanninen and H. Harma), Ch 2, Springer-Verlag, Berlin. 

Surveying the history of the theory of optical lanthanide spectroscopy, we can discern several main features the usefulness of Lie groups, following their introduction by Racah (1949) the relevance of the method of second quantization, as demonstrated by the use of annihilation and creation operators for electrons and the inability of the Hartree-Fock method and its various elaborations to provide accurate values (say to within 1%) of such crucial quantities as the Slater integrals F (4f,4f) and the Sternheimer correction factors R , for a free ion. The success of the formal mathematics is in striking contrast to the failure of the machinery of computation. This turn of events has happened over a period of time when... 

Such examples of applications of the tool of the lanthanide spectroscopy as mentioned here add impetus to the search for an extended J-0 model, which would be applicable for interpretation of entire lanthanide spectra in various compounds of macro and micro scales. 

Eliseeva S. V., J.-C. G. Biinzh, Chapter 1 in Lanthanide spectroscopy, Materials, and Bioapplications, Springer series on fluorescence, 7 (eds P. Hannen, H. Harma), Springer Verlag, Berlin, 2010. 

It may be helpful to explain the use of the terms rare earths and lanthanides throughout the text. By convenience, the term lanthanides refers to the elements La (Z = 57) to Lu (Z = 71). The term rare earths is commonly used for the lanthanides with inclusion of the elements Y (Z = 39) and Sc (Z = 21). Although one speaks often about rare-earth spectroscopy, the term lanthanide spectroscopy is preferable. The main objects of study in lanthanide spectroscopy are the trivalent lanthanide ions from Ce (4f ) to Yb3+ (4f ), since these ions have unpaired f electrons and can interact with ultraviolet, visible or near-infrared radiation. Divalent ions like Eu " " have gained less interest and will not be discussed here. The trivalent lanthanide ions La " (4f ) and Lu (4f ) are not spectroscopically active, because of an empty or filled 4f shell. The same is true for and Sc. Yttrium, lanthanum and to a lesser extent lutetium compounds are used as transparent host crystals in which other trivalent lanthanide ions can be doped. The trivalent lanthanide ions can readily substitute for Y, La " and Lu. Expressions like point group of the rare-earth site and the crystal field in rare-earth compounds are thus meaningful. 

The development of solid state lasers in the 1960s stimulated lanthanide spectroscopy, after it became clear that the trivalent lanthanide ions have promising lasing characteristics. The use of rare-earth ions in laser crystals has been discussed by Weber (1979) and by Kaminskii (1981). Crystals which came under examination are CaW04, LiYp4, Lap3,... 

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