Phosphorescence, quenching

However, the direct determination of absorption at the wavelength of maximum absorption is more sensitive (or in the worst case at least as sensitive) as the indirect measurement of absorption by fluorescence or phosphorescence quenching. 

This makes us conclude that the process of quenching is associated with an electron transfer. The efficiency of phosphorescence quenching by acceptors follows, as well, the growth of electron affinity of the latter. Phosphorescence quenching constants are two orders of magnitude lower than fluorescence quenching constants. This indi-... 

Phosphorescence quenching la 35 -, detection limits la 15 -, time dependance la 34 Phosphoric acid la 179,185,242,278,430 Phosphoric acid esters la 44,170 Phosphoric acid insecticides lb 115,332, 339,340... 

Sanz-Medel / Diaz-Garcia 1994 oxygen via RTP phosphorescence quenching of ferrone chelates... 

EM-values for intramolecular phosphorescence quenching in [25] as a function of chain-length m ... 

M Sudhakar, PI Djurovich, TE Hogen-Esch, and ME Thompson, Phosphorescence quenching by conjugated polymers, J. Am. Chem. Soc., 125 7796-7797, 2003. 

D 1A —- 1D + 1 A (triplet-singlet energy transfer). This type of transfer leads to phosphorescence quenching of the donor (e.g. phenanthrene (T) + rhod-amine B (S)). 

S. A. Bagnich and A. V. Dorokhin, Fractal character of phosphorescence quenching of diacetyl impurity in polymethyl methacrylate. Opt. Spectrosc. (USSR) 69, 833834(1990). 

Vanderkooi et al.(m) examined the phosphorescence from tryptophan in sarcoplasmic reticulum vesicles and the purified Ca transport ATPase at room temperature in deoxygenated solutions. The phosphorescence decay is multiexponential the lifetime of the long-lived component of phosphorescence is 22 ms. Addition of ATP or vanadate decreased the phosphorescence yield. The Ca2+-ATPase of the sarcoplasmic reticulum alternates between two conformations, called Ei and E2, during Ca2+ transport. The observations were interpreted to indicate that either the binding of vanadate or phosphate to the phosphorylation site of the ATPase or the induced shift in the conformation from the i to the E2 state produced the phosphorescence quenching. 

Biacetyl as sensitizer phosphorescence quenched fluorescence not affected, release of NH S No apparent degradation of biacetyl ... 

Bimolecular deactivation (pathway vii, Fig. 1) of electronically excited species can compete with the other pathways available for decay of the energy, including emission of luminescent radiation. Quenching of this kind thus reduces the intensity of fluorescence or phosphorescence. Considerable information about the efficiencies of radiative and radiationless processes can be obtained from a study of the kinetic dependence of emission intensity on concentrations of emitting and quenching species. The intensity of emission corresponds closely to the quantum yield, a concept explored in Sect. 7. In the present section we shall concentrate on the kinetic aspects, and first consider the application of stationary-state methods to fluorescence (or phosphorescence) quenching, and then discuss the lifetimes of luminescent emission under nonstationary conditions. 

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