Stern-Volmer plot emission

Fig. 1. a) UV-Vis absorption and fluorescence emission spectra of riboflavin (RF, 20 pM) and Gum Arabic aqueous solutions at pH 7 (phosphate buffer 100 mM). b) Transient absorption spectra of RF (35 pM) in N2-saturated MeOH-Water (1 1) solution. The insets show the transient decay at 720 nm for the RF species and the Stern-Volmer plot for the quenching of 3RF by GA, eqn 11. 

Figure 4. Stern-Volmer plots and quenching constants derived from the fluorescence quenching of DMA (T), 1,2,3,4-tetra-hydro-BA ( ), 5,6-dihydro-BA (A), 8,9,10,11-tetrahydro-BA ( ) and anthracene ( ) by DNA in 15% methanol at 23° C. Emission and excitation wavelengths and details concerning the experimental conditions are given in refs. 12 and 14. The open symbols, o and V, show I /I for 1,2,3,4-tetrahydro-BA and DMA respectively in denatured DNA([P04"] 4.4 x 10 4 M).

The quenching of pyrene monomer emission by 2-bromonaphtha-lene on dry silica gel has also been studied as a function of temperature. Linear Stern-Volmer plots are obtained either with t /t or with tJ/T], and t%/t2 vs tQ] where [Q] Is a surface concentration. Fig. 12 illustrates the f/f0 plot. The rate constants derived from... 

Figure 12. Effect of temperature on the quenching of pyrene monomer emission by 2-bromonaphthalene. Stern-Volmer plots at different temperatures.

Figure 2. (Top) Stern-Volmer plots for the quenching of the fluorescence of colloi fcl CdS in AOT-entrapped water pools in isooctane by RMV + (0), MV2+ 4Q), and PhSH (0) (Bottom) Absorption and emission spectra of colloidal CdS in AOT entrapped water pools in isooctane. The shoulder observed at 400 nm is due to a spectrometer artifact.

Figure 17 Stern-Volmer plots for the quenching of AMAC excimer emission (excitation at 374 nm and detection at 440 nm) by potassium iodide. O No BAZrP 0.001% BAZrP 0.01% BAZrP. (From Ref. 19. Copyright 1993 Elsevier Publications.)...

The emission spectrum of Ru(bpy)21 in HZrP and HexA-ZrP had maxima at 620-625 nm. In both cases, quenching by ferricyanide was used to distinguish between the Ru(bpy)2+ adsorbed on the outer surface and in the interlamellar regions. For HexA-ZrP, the Stern-Volmer plot was nonlinear and this nonlinearity was interpreted as due to the adsorption of Ru(bpy) + at two different places. The Stem-Volmer constant (KSv) for the major component was estimated to be 7200 M 1 and this value is of the same order of magnitude as that of Ru(bpy)f1 -kaolin [85], in which Ru(bpy)21 is known to bind on the external surface, and both values are much smaller than that observed in aqueous solution (23,000 M1) [75b],... 

Figure 7a. Effect of quenchers on the CdS emission intensity. CdS/SDS colloid Stern-Volmer plots for quenching by MV +...

Figure 3. Stern-Volmer plot of 7619-A. emission intensity for a series of...

Figure 14-14. Stern-Volmer plots of the relative emission intensity ( ) and lifetime ( ) against concentration for the electron transfer quenching of the photoexcited Ru(bpy)3 by MV in a 2 wt.% carrageenan/water solid (1x1x3cm size).

Figure 15. Stern-Volmer plots for the fluorescence quenching of zinc porphyrin in the myoglobin upon addition of MV at 10 mM phosphate buffer at 25 C. The solid lines correspond to the data obtained in rMb(156) (T), rMb(157) ( ), and rMb(158) ( ). The dashed line corresponds to the data obtained in native zinc myoglobin (A), [myoglobin] = 10 M. The changes of fluorescence emission were monitored at 584 nm = 543 nm).

Fig. 11. The Stern-Volmer plots for fluorescence quench-ing of 8, and 9 by in water monitoring monomer emission (O) or" exciirIer emission( ).

In the presence of static quenching, deviations from the linearity of the Stern-Volmer plots for emission and photoreaction quenching are expected, and the lifetime may apparently result unquenched [5]. The experimental quenching constant is related to the rate constants of the quenching process in the encounter (figure 11) by the following equation... 

By observing the disappearance of the a A X emission during ArF (193 nm) photolysis of HN3 in dilute mixtures with Q = N2, He, or Ar (semilogarithmic plots of the intensity at 789 nm vs. time (up to 5 ms) and Stern-Volmer plots of the decay rates x vs. total pressure at very small HN3 Q mixing ratios), the NH(a A) radicals were found to decay with rates faster than 33 s thus Xrad>003 s [4]. LIF due to A ITj -X excitation following 193-nm photolysis of HNCO and collision-induced a A X quenching by O2 yielded x ad O OS s [5]. (The disappearance of NH(a A) within less than 0.07 ms, observed by absorption [6], chemiluminescence [7, 8], and LIF [9] is due to chemical reactions with the parent molecules, see p. 121.)... 

Figure 2 Stern-Volmer plot for the dependence of the terbium emission intensity in 4b upon the concentration of dissolved molecular oxygen 370, 545 nm, emission measured 0.1 ms...

The Stern-Volmer equation says that, if we measure relative emission (0/q) as a function of quencher concentration and plot this quantity versus [Q], we should observe a straight line. The quantity <3>0/Oq in Equation 19-25 is equivalent to /,/Iq, where /0 is the emission intensity in the absence of quencher and Iq is the intensity in the presence of quencher. 

Figure 4. "Stern-Volmer" quenching plot of the phosphorescence emission of B phenylpropiophenone according to eq. 4 ...

Equation (3) is the well-known Stern-Volmer equation and kgv = kq r° is the Stern-Volmer quenching constant. In practice, the ratio of lifetime without to that with quencher is plotted against [B] and kq is obtained by dividing the slope by r°. Analogous Stem-Volmer equations can be obtained for the emission intensity and the reaction quantum yield... 

The intensity of the collision induced emission follows the order Xe > Kr > Ar > N2 > H2 > He (349, 436). According to Cunningham and Clark (254) this molecular emission is 40", of the total quenching process in the case of Xe, but it is only l"/ in the case of Ar. From the Stern-Volmer type plot of the intensity ratio of If (with added gas) to / (without added gas) against the pressure of an added gas, Black et al. (115) have recently obtained the rate constant for induced emission by He, Ar, N2, H2, Kr, and Xe. 

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