Optical properties, spectroscopy absorption

SnC>2 nanoparticles have been successfully synthesized by chemical co-precipitation method using ethanol, acetone, tetrahydrofuran (THF) and ether as solvents. X-ray Diffraction (XRD), Field Emission Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) have been used to study the crystallographic and morphological properties of synthesized SnC>2 nanoparticles, while their optical properties have been studied by UV-Visible absorption spectroscopy. UV-Vis absorption spectra shows a weak quantum confinement in all the synthesized SnCL samples. The photo-catalytic activity of as-synthesized SnC>2 nanoparticles under UV irradiation has been evaluated using Methylene Blue (MB) dye as a test contaminant in water. The results showed that solvents played a key role to control the morphology and photo-catalytic activity of SnCE nanoparticles. 

The luminescence of diamonds is related to various defects in its structure. Almost always, luminescence centers in diamonds are related to N atoms. It is logical, because the atomic radii of C and N are nearly equal (approximately 0.77 A). Luminescence spectroscopy has proven to be the most widely used method in studies of diamonds even in comparison with optical absorption, ESR, IR and Raman spectroscopies. Himdreds of spectra have been obtained, fluorescence characteristics enter into diamond quality gemological certificates, a wide range of electronic and laser applications are based on diamond optical properties in excited states nitrogen center aggregation is controlled by the residence time of diamond in the mantle, distinction between natural... 

Sample variability is a critical issue in prospective application. For optical technologies, variations in tissue optical properties such as absorption and scattering coefficients can create distortions in measured spectra. This section provides a brief overview of techniques to correct turbidity-induced spectral and intensity distortions in fluorescence and Raman spectroscopy, respectively. In particular, photon migration... 

The redox states of the flavin cofactor in a purified flavoenzyme can be conveniently studied by optical spectroscopy (see also Elavoprotein Protocols article). Oxidized (yellow) flavin has characteristic absorption maxima around 375 and 450 nm (Fig. lb and Ic). The anionic (red) and neutral (blue) semiquinone show typical absorption maxima around 370 nm and 580 nm, respectively (Fig. lb and Ic). During two-electron reduction to the (anionic) hydroquinone state, the flavin turns pale, and the absorption at 450 nm almost completely disappears (Fig. lb and Ic). The optical properties of the flavin can be influenced through the binding of ligands (substrates, coenzymes, inhibitors) or the interaction with certain amino acid residues. In many cases, these interactions result in so-called charge-transfer complexes that give the protein a peculiar color. 

Finally, forward ISRS excitation can be followed by measurement of time-dependent absorption or Raman spectra, second harmonic generation efficiency, or any other optical property that may be affected by vibrational distortion. Preliminary time-resolved absorption spectroscopy of nonequilibrium, vibrationally distorted species is discussed further in the next section [46]. 

The synthesized products were obtained as colloidal solutions. Optical properties, morphology and composition of the nanoparticles were investigated by means of optical absorption spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. 

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