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.