Welcome to Loot.co.za!
Sign in / Register |Wishlists & Gift Vouchers |Help | Advanced search
|
Your cart is empty |
|||
Showing 1 - 5 of 5 matches in All Departments
The rare earths play a unique role in science. These seventeen
related elements afford a panoply of subtle variations deriving
from the systematic development of their electronic configurations,
allowing a test of theory with excellent resolution. In contrast
they find widespread use in even the most mundane processes such as
steel making, for polishing materials and gasoline cracking
catalysts. In between are exotic uses such as TV screen phosphors,
lasers, high strength permanent magnets and chemical probes.
Optical spectroscopy has been instrumental in the discovery of many
lanthanide elements. In return, these elements have always played a
prominent role in lighting devices and light conversion
technologies (Auer mantles, incandescent lamps, lasers, cathode-ray
and plasma displays). They are also presently used in highly
sensitive luminescent bio-analyses and cell imaging. This volume of
the Handbook on the Physics and Chemistry of Rare Earths is
entirely devoted to the photophysical properties of these elements.
It is dedicated to the late Professor William T (Bill) Carnall who
has pioneered the understanding of lanthanide spectra in the 1960 s
and starts with a Dedication to this scientist. The following five
chapters describe various aspects of lanthanide spectroscopy and
its applications. Chapters 231 presents state-of-the-art
theoretical calculations of lanthanide energy levels and transition
intensities. It is followed by a review (Chapter 232) on both
theoretical and experimental aspects of f-d transitions, a less
well known field of lanthanide spectroscopy, yet very important for
the design of new optical materials. Chapter 233 describes how
confinement effects act on the photophysical properties of
lanthanides when they are inserted into nanomaterials, including
nanoparticles, nanosheets, nanowires, nanotubes, insulating and
semiconductor nanocrystals. The use of lanthanide chelates for
biomedical analyses is presented in Chapter 234; long lifetimes of
the excited states of lanthanide ions allow the use of
time-resolved spectroscopy, which leads to highly sensitive
analyses devoid of background effect from the autofluorescence of
the samples. The last review (Chapter 235) provides a comprehensive
survey of near-infrared (NIR) emitting molecular probes and
devices, spanning an all range of compounds, from simple chelates
to macrocyclic complexes, heterometallic functional edifices,
coordination polymers and other extended structures. Applications
ranging from telecommunications to light-emitting diodes and
biomedical analyses are assessed.
This volume of the Handbook adds five new chapters to the science of rare earths. Two of the chapters deal with intermetallic compounds. An overview of ternary systems containing rare earths, transition metals and indium - Chapter 218 - opens the volume. It is followed by Chapter 219 sorting out relationships between superconductivity and magnetism. The next two chapters are dedicated to complex compounds of rare earths: Chapter 220 describes structural studies using circularly polarized luminescence spectroscopy of lanthanide systems, while Chapter 221 examines rare-earth metal-organic frameworks, also known as coordination polymers. The final Chapter 222 deals with the catalytic activity of rare earths in site-selective hydrolysis of DNA and RNA.
Even at the beginning of the new millenium the rare earths still
remain, to a certain extent, a mystery. The chapters in this volume
will help to unravel some of these. In the filling of the 4f
electronic orbitals the lanthanides defy the elementary aufbau
principle that underlies the periodic sequence of the elements, and
the authors of the first chapter introduce the readers to the basic
physics of the orbital collapse leading to that failure.
Furthermore an explanation is offered in terms of double-well
potentials. The phenomenon is illustrated using the valence
transitions observed in some of the rare earth atoms, including Sm
group metals and the higher oxides of cerium, praseodymium and
terbium. In the second chapter the synthesis and structure of the
many types of rare earth halides are described. They have been
described as simple, complex, binary, ternary and multinuclear
complex, and other categories needed to deal with the most studied
of the rare earth compounds. The structure types are skillfully
illustrated to show the elementary architecture of each type.
This volume of the Handbook on the Physics and Chemistry of Rare
Earth begins with a Dedication to late Professor LeRoy Eyring who
had been a committed co-editor of the first 32 volumes of this
series. This is followed by four chapters, the first two pertaining
to solid state physics and materials science, while the last two
chapters describe organic (and inorganic) reactions mediated by
tetravalent cerium-based oxidants and by divalent samarium-based
reductants. Chapter 227 is devoted to the description of the
crystal chemistry and physical properties of rare-earth
bismuthides, a class of compounds showing large similarities with
the rare-earth antimonides previously reviewed in volume 33 of this
series. The fascinating optical and electric properties of
rare-earth hydride films displaying a switchable mirror effect as a
function of hydrogen pressure, i.e. from a shiny metallic state to
a transparent insulating film with increasing pressure, are
described in Chapter 228, along with their fabrication methods.
Many chemical reactions take advantage of the tetravalent/trivalent
Ce(IV)/Ce(III) redox couple and many of its potential applications
are presented in Chapter 229, from analytical procedures, to
electrosynthesis, and organic and industrial (polymerization)
reactions. The last review (Chapter 230) focuses on the synthesis
and use of divalent samarium-based reductants in organic and
inorganic reactions, mainly on those containing iodide and
pentamethylcyclopentadienyl ligands.
|
You may like...
|