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Showing 1 - 5 of
5 matches in All Departments
1. R.C. Mehrotra, Jaipur, India Present Status and Future Potential
of the Sol-Gel Process 2. J. Fricke, A. Emmerling, Wuerzburg, FRG
Aerogels - Preparation, Properties, Applications 3. S. Sakka, T.
Yoko, Kyoto, Japan Sol-Gel-Derived Coating Films and Applications
4. H. Schmidt, Saarbruecken, FRG Thin Films, the Chemical
Processing up to Gelation 5. M. Henry, J.P. Jolivet, J. Livage,
Paris, France Aqueous Chemistry of Metal Cations: Hydrolysis,
Condensation and Complexation 6. R. Reisfeld, Jerusalem, Israel,
C.K. Joergensen, Geneva, Switzerland Optical Properties of
Colorants or Luminescent Species in Sol-Gel Glasses
The possibility of stimulated light emission was discussed by
Einstein in 1917, eight years before the quantum-mechanical
description of energy levels of many-electron systems. Though it is
imperative to use samples having optical properties greatly
different from the stan dard continuous spectrum of opaque objects
("black body" radia tion) it is not always necessary to restrict
the study to monatomic entities. Thus, spectral lines can be
obtained (in absorption and in emission) from lanthanide compounds,
containing from one to thir teen 4f electrons going from trivalent
cerium to ytterbium, that are nearly as sharp as the ones from
gaseous atoms. However, the presence of adjacent atoms modifies the
simple picture of an isolated electron configuration, and in
particular, it is possible to pump excited levels efficiently by
energy transfer from species with intense absorption bands, such as
the inter-shell transitions of other lanthanides and of
thallium(I), lead(II) and bismuth(III) or the electron transfer
bands of the uranyl ion or other complexes. On the other hand, it
is possible to diminuish the mUlti-phonon relaxation (competing
with sharp line luminescence) by selecting vitreous or crystalline
materials with low phonon energies. Obviously, one cannot
circumvent the conservation of energy by lasers, but they may have
unprecedented consequences for the future by allowing nuclear
fusion of light elements, effects of non-linear optics and
time-resolved spectroscopy, besides the more conventional
applications of coherent light beams with negligible angular
extension."
Luminescence Spectroscopy of Minerals and Materials presents an
overview of the general concepts in luminescence spectroscopy as
well as experimental methods and their interpretation. Special
emphasis is laid on the fluorescence lifetime and the determination
of time-resolved spectra. This method enables the exposure of new
luminescence in minerals previously hidden by more intensive
centers. Specialists in the fields of solid state physics,
chemistry and spectroscopy will find a wealth of new information in
this unique book.
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