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The amino and hydroxy anthraquinones possess numerous chemically
and biologically significant properties and as a group are also of
considerable practical importance in the production of dyes &
intermediates and as model compounds to gain fundamental
information. These derivatives of anthraquinones have found
important applications as prominent family of pharmaceutically
active and biologically relevant chromophores. A detailed and
comprehensive study of electronic absorption spectra of
anthraquinone and its hydroxy and amino derivatives and their
theoretical interpretation are presented. The effect of solvents on
the electronic absorption spectra of anthraquinones is studied
using twenty four solvents of different polarities. A careful study
of the effect of solvents on the electronic spectra of
anthraquinones reveals that the hydrogen bonding effects are of
considerable importance in understanding the spectral shifts in the
charge transfer transitions. The spectral shifts in various
solvents indicate that their values mainly depend on the strength
of the hydrogen bonds between the substituent groups and the
solvent molecules and the extent of the intramolecular hydrogen
bonding.
Semiconductor clusters have one extraordinarily important property
that on doping and on changes in size, their properties change
appreciably and in a controllable way. Current research into
semiconductor clusters is focused on the properties of thin films
having nanometre range grain size. The wide range of optical and
electrical properties of II-VI group compounds make them an
important class of materials and competing candidates for silicon
and other semiconductor materials in photovoltaic and
optoelectronic applications. In this monograph, the structural,
spectroscopic and optoelectronic properties of Cadmium Sulfide,
Cadmium Telluride and Zinc Oxide thin films are studied in detail.
The effects of substrate and grain size on structural and optical
properties of these materials are also discussed. Moreover, the
synthesis of CdS nanoparticles and fabrication of ZnO thin films by
the sol-gel methods and their spectroscopic characterization are
described. The ab-initio DFT calculations are carried for the
computations of the DOS and band structures of the CdS hexagonal
wurtzite, CdTe zinc blende and ZnO hexagonal wurtzite. Effect of Cd
dopping in ZnO is also studied theoretically.
Fullerenes are the third allotrope of carbon and have received much
attention due to their unique properties. In this monograph on
'Optical Gain and Relaxation Mechanism of Fullerenes in Solutions',
the effect of concentration of Fullerenes C60 and C70 molecules on
their fluorescence spectra are studied in detail. Moreover,
Forster's Resonance Energy Transfer (FRET) from different dyes to
the fullerenes are investigated and it has been found that
Fullerene C60 -Coumarin C440 pair and also Fullerene C70 -
Quinizarine pair may be used as spectroscopic rulers. Time Resolved
Spectra of both the fullerenes in pure as well as in mixture form
were measured and the results show that the optical gain is
concentration-dependent and only Fullerene C70 shows positive gain,
which can be used as a lasing material.
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Loot
Nadine Gordimer
Paperback
(2)
R398
R330
Discovery Miles 3 300
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