Luminescence spectral properties

The nature of the lowest-lying excited states of the fullerenes has been difficult to identify with much certainty. From Shpol skii-type luminescence spectra recorded at 1.5 K it has been concluded that the first-excited singlet state in C70 is of A 2 character. The origins of the lowest energy transitions in Ceo, namely Si(T]g) and S2(Gg), have been assigned on the basis of fluorescence and excitation spectra, supported by theoretical calculations. " The luminescence properties and relaxation dynamics of single crystals of Qo have been described while related measurements have been made for solid films of Ceo " Similar studies have reported the luminescence spectral properties of 50 trapped inside the cavities of NiY zeolites. An analysis of the fine structure of electron-vibrational spectra has been made for 50 and its derivatives in a solid toluene matrix. The rate of triplet energy transfer between fullerenes in toluene solution has been measured as a function of temperature and used to derive thermodynamic parameters for the transfer process. ... 

Miscellaneous. The systematics of molecules according to their luminescence spectral properties,484 the interpretation of fluorescence parameters,485 a simple... 

Spectral Tuning in Complexes Containing Hybrid Donor Ligands The absorption and luminescence spectral properties of complexes of the type [Ru(dmbip) (dcbpy)(X)] and [Ru(dmbip)(dcbiq)pC)], where dmbip = 2,6-bis(l-methylbenzimid-azol-2 -yl)pyridine, dcbpy=4,4 -(COOH)2-... 

The luminescence spectral properties of rare earth ions such as Eu+3 (4f ) and Tb+3 (4f ), Sm+3 (4P) and Dy+3 (4f ) in the heavy-metal borate glasses have shown interesting and encouraging results [10, 11]. Eu+3 and Tb+3 ions have shown prominent emissions (red and green) in the visible wavelength region, while Sm+ and Dy+3 show strong absorption bands... 

Nizomov, N. Ismailov, Z. F. Kurtaliev, E. N. Nizamov, Sh. N. Khodzhaev, G. Patsenker, L. D. Luminescent spectral properties of rhodamine derivatives while binding to semm albumin. J. Appl. Spectrosc. 2006, 73, 432—436. 

Lakowicz et al. [96] have studied luminescence spectral properties of CdS nanoparticles. They examined the steady state and time resolved luminescence spectral properties of two types of CdS nanoparticles. These results suggest that nanoparticles can provide a new class of luminophores for use in chemical sensing, DNA sequencing, high throughput screening and other biotechnology applications. 

The spectral properties of four major phycobiliproteins used as fluorescent labels can be found in Tables 9.1 and 9.2. The bilin content of these proteins ranges from a low of four prosthetic groups in C-phycocyanin to the 34 groups of B- and R-phycoerythrin. Phycoerythrin derivatives, therefore, can be used to create the most intensely fluorescent probes possible using these proteins. The fluorescent yield of the most luminescent phycobiliprotein molecule is equivalent to about 30 fluoresceins or 100 rhodamine molecules. Streptavidin-phycoerythrin conjugates, for example, have been used to detect as little as 100 biotinylated antibodies bound to receptor proteins per cell (Zola et al., 1990). 

Fig. 3 Chemical structures and typical spectral properties of the common luminescent emitters used for staining of polymeric beads...

Colloidal CdS particles 2-7 nm in diameter exhibit a blue shift in their absorption and luminescence characteristics due to quantum confinement effects [45,46]. It is known that particle size has a pronounced effect on semiconductor spectral properties when their size becomes comparable with that of an exciton. This so called quantum size effect occurs when R < as (R = particle radius, ub = Bohr radius see Chapter 4, coinciding with a gradual change in the energy bands of a semiconductor into a set of discrete electronic levels. The observation of a discrete excitonic transition in the absorption and luminescence spectra of such particles, so called Q-particles, requires samples of very narrow size distribution and well-defined crystal structure [47,48]. Semiconductor nanocrystals, or... 

The emission properties of lumophores change when included within the microenvironment of a supramolecule bucket. Nonradiative decay processes are generally curtailed within the confines of the bucket interior and luminescence intensity is therefore increased [138,208,209], Because CDs present a more protected microenvironment than calixarenes, the binary complexes of the former supramolecule have been examined most extensively. Spurred by Cramer s pioneering observation that the spectral properties of a lumophore are perturbed by complexation within a CD [210], a large body of work has sought to define the influence of CDs on the photophysics of bound lumophores. Different factors contribute to the enhanced luminescence of 1 1 CDilumophore complexes. These include the following. 

Related NACAN-coordinated complexes containing benzothiazoles 50 or azaindoles 51 in place of the pyridyl rings have also been investigated [140,141]. Complex 50 is luminescent in solution at room temperature, with tt-tt spectral properties resembling monomeric [Pt(dpyb)Cl], whilst the azaindole complexes are emissive only in the solid state or in glasses at 77 K. 

A recent review discusses the synthesis, spectral properties, and photochemical behavior of novel spirobenzopyrans, Spiro-1,4-oxazines, and 2//-chromenes. It emphasizes the structural features needed for infrared-absorbing photoisomers, luminescent stable forms, improved fatigue resistance, and spiropyrans exhibiting photochromism in vacuum-deposited films.147... 

Miller and King (1975) studied the differing luminescence properties of lysozyme and a-lactalbumin. For the latter the spectral properties observed were attributed to the proximity of Trp residues to S—S bonds, the reduction of which caused much change, as did acid denaturation. Their work supports the earlier suggestion by Sommers et al. (1973), that energy is transferred from Trp-109 to Trp-63 in the active site cleft, with subsequent quenching of the latter by neighboring cystine residues. 

The chromato phic (TLC, i8.i . io,4i 1 gc,i and HPLC ) and polaro-graphic behavior and mass spectral properties - - of some pyr-rolo[2,l-i>]quinazoline alkaloids were investigated. A procedure for the rapid qualitative identification of vasicine (184) by means of capillary luminescence was developed. ... 

Figure 4-10 General design for in vitro optical sensor designed to detect given analyte in blood sample. Polymer film contains dye that changes spectral properties in proportion to the amount of analyte in the sample phase. Example shown is for sensing film that changes luminescence (fluorescence or phosp horescence).

Answers to the key questions about surface phenomena have been obtained by use of luminescence probing techniques. In general, a lumophore is isolated at an interface. On the basis of steady-state and time-resolved spectral properties of the lumophore in neat solution or in simple organized media (4), the energy, spectral shape, and time-resolved decay... 

The high electron density existing inside the CD cavity can grip the electrons of the encapsulated guest molecules, and result in a various spectral properties of both the guest and host [61]. This effect of CDs on the spectral properties of guest molecules has led to their utilization in various spectrometric analyses, such as UV/VIS spectrophotometric analysis, fluorescence and luminescence spectroscopy and NMR spectroscopy. 

Prior to eiqieiimentation, it is often useful to know which molecales are fluorescait and what is known about their spectral properties. Such information has been gathered in a systematic manner in Part I of Molecular Luminescence Spectroscopy (Schuiman, 1985). Subsequent volumes of this usefid series contain information on qtedalized topics such... 

Spectral properties of AIN, including absorption and luminescence in the visible and UV range, actual for practical application are determined by a wide band gap ( g = 6.2 eV) of the material and presence of lattice defects and impurities. In the form of ceramics, AIN maintains almost all properties of single crystals, except that if no special measures are undertaken ceramics are not transparent. Translucent AIN ceramics can be produced by choosing the appropriate concentration and type of sintering aid, such as CaFj [25] or Ca3Al20g [26]. 

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