Fluorescence emission and excitation

Fig. 5 Fluorescence emission and excitation spectra of AvGFP at 293K, 0.5 pM in 10 mM Tris...

Figure 8.2. Fluorescence emission and excitation spectra of a strongly scattering sample as detected in forward (Ff) and backward (Fb) direction. (Pyrene adsorbed on silica gel, surface loading cpyr = 5.5-10-7 mol g l, spec, surface area cisiiica = 500 m2 g ),...

Time-Resolved Fluorescence. Emission and excitation monochromators are maintained in a specific wavelength, but the excitation is chopped off and fluorescence decay is measured as a function of time. This kind of spectroscopy is interesting for studying structural changes or different complexation sites. 

Zhadin NN, Alfano RR. Correction of the internal absorption effect in fluorescence emission and excitation spectra from ahsorhing and highly scattering media theory and experiment. Journal of Biomedical Optics 1998, 3, 171-186. 

The same studies were performed with calf thymus DNA. In addition to the absorption and emission spectra, we have recorded the fluorescence excitation spectra of ethidium bromide at different DNA concentrations (Figure 12.12). One can see that the increase in fluorescence intensity stops when the stoichiometry of the complex is reached. Binding parameters (n = 2.6 and Krl = 3 x 105 M-1) determined from the fluorescence excitation intensities are found to be equal to those calculated with the fluorescence emission and the OD variations. Figure 12.13 shows the normalized intensity increase in both fluorescence emission and excitation intensity peaks of ethidium bromide with the function of DNA. The intensity increase in the excitation spectrum of ethidium bromide in the presence of DNA is the result of binding of the fluorophore to DNA and thus of the increase in the number of excited bound fluorophores. 

The fully hydrated samples do not show any fluorescence or absorption in the wavelength ranges examined. However, when submitted to vacuum treatment at increasing temperature, the zeolite samples show fluorescence emission and excitation spectra whose intensity increases up to 500°C. In Figure 3A the excitation and emission profiles for AgxNaYsoo are presented. These profiles remain essentially invariant after oxygen treatment at 400°C. 

Diffuse reflectance spectra (A) of Agg NaX taken during dehydration under vacuum and oxygen treatment (400 torr). Fluorescence emission and excitation profiles (B) corresponding to stage C in Figure 5(A) (15). 

Fluorescence emission and excitation spectra of Ag,NaY..n and Ag NaXcQQ- Note that the weak shoulder seen+arouna 280 nm for the excitation spectra is probably due to Ag (15). 

At this point we note that the overall form of the absorption, fluorescence emission and excitation profiles for Agx, Ag + and AgP+ for AgxNaX and AgxNaY is superficially reminiscent of those observed for Ag°, Ag2 0, and Ag3 ° entrapped in rare gas solids (4-10). However, a number of important differences are also apparent. These details are discussed for each silver guest as a necessary prelude to the subject of metal-support interactions. 

The overall orm, but not the detail, of the fluorescence emission and excitation profiles for Ag° atoms in site I of X and Y zeolites is similar to those observed for... 

Fig. 10. Fluorescence emission and excitation (or absorption) spectra in CSj of p-carotene (A) and fucoxanthin (B). See text for details. Figure source (A) Glllbro and Cogdell (1989) Carotenoid fluorescence. Chem Phys Lett. 158 313. (B) Katoh, Nagashima, and Mimuro (1991) Fluorescence properties of the allenic carotenoid fucoxanthin impiication for energy transfer in photosynthetic pigment systems. Photosynthesis Res 27 223.

Figure 4.23 Absorption, fluorescence emission ( ) and excitation spectra of cycl[3.3.3]...

The fluorescence emission and excitation spectra for a solution of 1 were reported in [7]. We recorded the fluorescence emission spectra excited by the 457.9 nm laser line for both la and Id as solids (Fig. 5). The Xmax values of these broad bands differ significantly (ca. 560 and 515 nm, respectively) in good accord with the position of electronic absorption bands. A large Stokes shift points to a substantial geometry change upon excitation. Under illumination, Id slowly transformed into la (see Fig. 5, lower curves). 

Figure 1. The fluorescence emission and excitation spectra of di aikyiaminobenzylidenemalononitriies. 1, 2, and 3 is ethyl acetate at room temperature.

---