Volmer relationship

The importance of comparing time-dependent and steady-state fluorescence measurements is well illustrated by the difficulty of resolving purely static from purely dynamic quenching. In either case, the basic relationship between the steady-state fluorescence intensity and quencher concentration is the same. The Stem-Volmer relationship for static quenching due to formation of an intermolecular complex is i... 

The interaction of an extrinsic membrane protein with a lipid bilayer can also be investigated by energy transfer. The interaction of cytochrome c has attracted much attention, and in an early study by Shaklai et al.(()5> the number of binding sites per red cell was determined. It was shown that an equation analogous to the Stem-Volmer relationship could be derived ... 

This is the Stern-Volmer relationship with = k /k(j, and is an important basis for determining quenching rate constants after pulsed excitation. The quantum yield of (pro-duct)o can be measured without (0q) and with (0) quencher under continuous excitation (0 = moles of product/einsteins of light absorbed by system). Assuming that a steady state concentration of S exists in both cases. 

This equation is known as the Butler-Volmer relationship. Figure 2.12 shows that the net current flowing at an electrode can be considered as the... 

The Volmer relationship may acquire simpler limiting forms. If the final term in eqn. (40) is negligible in comparison with the other two, the approximation... 

This relationship may be inserted back into the general case of eqn. (40) to produce an alternative formulation of the Butler—Volmer relationship. 

This is the well known Stem-Volmer relationship which relates the number of photons absorbed per unit volume per second (/,) to the number emitted per unit volume per second (/f). The quantity 7f//a is the emission efficiency and is often given the symbol Q. 

As shown in Table 9.1, the typical timescale for the electrochemistry ( Cell Charging Time ) is on the order of 10-5 s. As a result, it is often that this transient is ignored in cell performance calculations, and the quasi-steady Butler-Volmer relationship is used alone (Qi et al., 2005). An example model for this particular type of dynamic cell behavior is given in Section 9.5. 

Volmer relationship and steady-state approximations, the kinetic scheme of Fig. 13 leads to Eq. (38) where kq is the... 

Since iodide is known to act in phospholipid vesicles as a collisional quencher for AF probes [6,9] by a diffusive process, fluorescence quenching was described by the Stem-Volmer relationship [6] ... 

Analysis of this scteme ows that for steady-state excitation, the Stern-Volmer relationship (62) and quantum yield ratio of excimer to monomer fluorescence (63) are obtained. 

The change in radical lifetimes on Vycor glass which had been degassed at various temperatures was determined by the effect of O2 upon the CgHg formation by means of the Stern-Volmer relationship ... 

Another mathematical model based on the relative contributions of static and dynamic quenching mechanisms in heterogeneous systems was derived by Carraway etal [8]. The light intensity in their model is described by a series of Stern-Volmer relationships... 

The graph below shows the Stem-Volmer plots for quenching of the luminescence of polysilole 1, by TNT in toluene solution. A linear Stem-Volmer relationship is observed for the corresponding polygermole, 2, and the copolymers 3-8, but the Stem-Volmer plot for quenching by picric acid... 

The presence of a freely diffusing quencher, however, underlies the essential difference between energy-transfer studies in the liquid and solid phases, although it is still possible to relate the Stem-Volmer relationship to quenching data in the solid. This has been demonstrated in the quenching of phosphorescence of poly(acenaphthylene) (23), poly(1-vinylnaphthalene) (24) and poly(styrene) (25) by piperylene in glasses at 77°K. 

From Eqs. (16), (19), and the Butler-Volmer relationship, the following relation is obtained ... 

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