Laser lanthanides

Modem methods for study of metal-activated enzymes include NMR and ESR spectroscopy, water relaxation rates by pulsed NMR (PRR), atomic absorption, Mbssbauer, X-ray and neutron diffraction, high-resolution electron microscopy, UV/visible/IR spectroscopy, laser lanthanide pertubation methods, fluorescence, and equilibrium and kinetic binding techniques. Studies with Mg(II)-activated enzymes have been hampered by the lack of paramagnetic or optical properties that can be used to probe its environment, and the relative lack of sensitivity of other available methods initial velocity kinetics, changes in ORD/CD, fluorescence, or UV properties of the protein, atomic absorption assays for equilibrium binding, or competition with bound Mn(II) °. Recent developments in Mg and 0-NMR methodology have shown some promise to provide new insights . ... 

Lanthanide luminescence apphcations have already reached industrial levels of consumption. Additionally, the strongly specific nature of the rare-earths energy emissions has also led to extensive work in several areas such as photostimulable phosphors, lasers (qv), dosimetry, and fluorescent immunoassay (qv) (33). 

Solid-State Lasers. Sohd-state lasers (37) use glassy or crystalline host materials containing some active species. The term soHd-state as used in connection with lasers does not imply semiconductors rather it appHes to soHd materials containing impurity ions. The impurity ions are typically ions of the transition metals, such as chromium, or ions of the rare-earth series, such as neodymium (see Lanthanides). Most often, the soHd material is in the form of a cylindrical rod with the ends poHshed flat and parallel, but a variety of other forms have been used, including slabs and cylindrical rods with the ends cut at Brewster s angle. 

Fluorescence and Glass Lasers. Some ions absorb light of a certain frequency emitting light of lower frequency. This is known as fluorescence. Examples of ions that fluoresce in glass are Mn(TV), Pb(II), and the lanthanide ions. 

Lanthanides Elements 57 (La) through 70 (Yb) in the periodic table, 146 Lanthanum, 147 Laser fusion, 528 Lattices in ionic crystals, 249 Lavoisier, Antoine, 14 Law of conservation of energy A natural law stating that energy can neither be created nor destroyed it can only be converted from one form to another, 214... 

Selvin, P. R. (1996). Lanthanide-based resonance energy transfer. IEEE Journal of selected topics in quantum electronics Lasers Biol. 2, 1077-1087. 

Lanthanide ion catalysts, alcoholysis with, see Transition metal ion and Ln3+ catalysts, alcoholysis Laser flash photolysis (LFP), 170, 175-178 cyclodextrins (CD), binding dynamics of guests binding to, 215-216 DNA, binding dynamics of guests binding to, 193-194... 

Double-pulse ruby laser, 14 697-698 Double refraction, 14 675 Double salts, lanthanide, 14 633-634 Double-stranded DNA viruses, 3 135... 

Contents Analogies and Differences Between Monatomic Entities and Condensed Matter. -Rare-Earth Lasers. - Chemical Bonding and Lanthanide Spectra. - Energy Transfer. - Applications and Suggestions. 

The rare earth (RE) ions most commonly used for applications as phosphors, lasers, and amplifiers are the so-called lanthanide ions. Lanthanide ions are formed by ionization of a nnmber of atoms located in periodic table after lanthanum from the cerium atom (atomic number 58), which has an onter electronic configuration 5s 5p 5d 4f 6s, to the ytterbium atom (atomic number 70), with an outer electronic configuration 5s 5p 4f " 6s. These atoms are nsnally incorporated in crystals as divalent or trivalent cations. In trivalent ions 5d, 6s, and some 4f electrons are removed and so (RE) + ions deal with transitions between electronic energy sublevels of the 4f" electroiuc configuration. Divalent lanthanide ions contain one more f electron (for instance, the Eu + ion has the same electronic configuration as the Gd + ion, the next element in the periodic table) but, at variance with trivalent ions, they tand use to show f d interconfigurational optical transitions. This aspect leads to quite different spectroscopic properties between divalent and trivalent ions, and so we will discuss them separately. 

Polymer-salt complexes involving the tripositive lanthanides have been investigated from the standpoint of conductivity, which is observed to be very low. In addition, the neutral complex Nd(DMP)3 (DMP = 2,2,6,6-tetraethyl,-3,5-heptane dionate) will dissolve in PEO although not electrically conductive this polymer may have utility as a laser material. To... 

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