Quenching of luminescence

In order to address the possible influence of positional disorder, we have chosen to analyze the way basic operations such as translations and rotations affect the properties calculated for highly symmetric configurations. This approach could provide guidelines to prevent the loss of significant optical coupling between the ground state and the lowest excited state, and hence the quenching of luminescence in the solid state. 

Kautsky H., Hirsch A. Energy transformations on boundary surfaces. IV. Interaction of excited dyestuff molecules and oxygen. Chem. Ber. 1931 64, 2677. For a review, see Kautsky H., Quenching of luminescence by oxygen, Trans. Faraday Soc. 1939 35 216. 

M. Gouterman, Oxygen quenching of luminescence of pressure sensitive paint for wind tunnel research ,/ Chem Educ. 1997, 74, 697-702. 

The Stern-Volmer method of monitoring the quenching of luminescence can also be applied to the quenching of phosphorescence emission. 

Similarly to bulk oxygen sensors, optical nanosensors rely on dynamic quenching of luminescence. Numerous indicators and polymeric materials were found suitable... 

Fig. 11 Plot of the luminescence intensity of an aqueous solution of Au23 against the ions added externally to the solution. The concentration of Au23 was the same for all the experiments. Clusters showed specific reactivity toward Cu2+ ions with significant quenching of luminescence. Photographs of the aqueous solution of Au23 in the presence of externally added ions under UV light irradiation are also given. The photograph was collected immediately after the addition of metal ions [15]...

L. Sacksteder, J. N. Demas, and B. A. DeGraff, Design of oxygen sensors based on quenching of luminescent metal complexes Effect of ligand size and heterogeneity, Anal. Chem. (submitted). 

In principle, an increase in the concentration of a luminescent center in a given material should be accompanied by an increase in the emitted light intensity, this being due to the corresponding increase in the absorption efficiency (see expression (1.15)). However, such behavior only occurs up to a certain critical concentration of the luminescent centers. Above this concentration, the luminescence intensity starts to decrease. This process is known as concentration quenching of luminescence. 

The quenching of luminescence by d-block ions is not universal 53 is an unusual illustration. Even in more common situations, different oxidation states of the same metal can act very differently. Some cases are clear. Cu(II) quenches the lumines-... 

The other way to study the "conductivity of protein molecules towards electron tunneling is to investigate the quenching of luminescence of electron-excited simple molecules by redox sites of proteins [95,96]. Experiments of this sort on reduced blue copper proteins have involved electron-excited Ru(II)(bpy)3, Cr(III)(phen)3, and Co(III)(phen)3 as oxidants. The kinetics of these reactions exhibit saturation at protein concentrations of 10 3 M, suggesting that, at high protein concentrations, the excited reagent is bound to reduced protein in an electron transfer precursor complex. Extensive data have been obtained for the reaction of reduced bean plastocyanin Pl(Cu(I)) with Cr(III)(phen)3. To analyze quenching experimental data, a mechanistic model that includes both 1 1 and 2 1 [Pl(Cu(I))/ Cr(III)(phen)3] complexes was considered [96]... 

R Jakubiak, CJ Collison, WC Wan, LJ Rothberg, BR Hsieh. Aggregation quenching of luminescence in electroluminescent conjugated polymers. J Phys Chem A 103 14, 2394-2398, 1999. 

In most cases, quenching of luminescence of CdS colloids is determined by the reactions of interfacial electron transfer involving either electron or hole. So, study of this process is a convenient method for establishing the regularities of key steps of redox photocatalytic reactions over CdS. In addition, using of various luminescence quenchers (anions, cations, and neutral molecules) allows to reveal the nature of electron capture sites at the CdS surface. 

Figure 16.1 Main classes of fluorescent molecular sensors of ions and molecules based on (a) quenching of luminescence by collisions with analyte (b) quenching or (c) increase of fluorescence of the complexing fluorophore (d,e) the same processes in fluorophore-receptor assemblies [1]...

The study by Connick et al. (112) not only points to the importance of investigating self-quenching of luminescence from square-planar platinum(II)... 

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