Yields, fluorescence photon

Fluorescence Photon Yields We previously estimated the experimental fluorescence photon yield of PuF6 excited at 1064 nm as well as at 532 nm as being 10 (1). We define... 

Non-Radiative Decay Channels - 1064 nm Excitation. We turn now to a comparison of the observed fluorescence photon yield defined by Equation 1 and the expected fluorescence quantum yield of the 4550 cm 1 state which indicates that several non-radiative decay channels may be open following 1064 nm excitation of PuF6(g) The following relationship between... 

Figure 3. Energy diagram for 1064 nm excitation of PuFg(g). The 5f electron states of PuF6 are shown at the left. The solid arrows Indicate photon absorption or emission processes. The wavy arrows indicate nonradiative processes by which excited states of PuF6 are lost. Comparison of observed fluorescence photon yields versus the fluorescence quantum yield expected for the 4550 cm" state indicate that the PuFg state initially populated following 1064 nm excitation may dissociate as shown.

Pump laser photon absorption, fluorescence photon yield. 163-64... 

Measured end points are photosynthesis as the incorporation of radiolabelled H C03 ( C) and bacterial activity as the incorporation of radiolabelled thymidine (thym) fluorometric measurements basal fluorescence (Fo) and photon yield (Y) chlorophyll-a concentration (chl-a) species composition (spp) and the biovolume of algae obtained after algal counting (biovolume)... 

Bjorkman, O. (1987). Low-temperature chlorophyll fluorescence in leaves and its relationship to photon yield of photosynthesis in photoinhibition. In Photoinhibition, ed. D.J. Kyle, C.B. Osmond and C.J. Arntzen, pp. 123-44. Amsterdam Elsevier. 

Bjorkman, O. Demmig, B. (1987). Photon yield of oxygen evolution and chlorophyll fluorescence characteristics at 77 K among vascular plants of diverse origins. Planta, 170, 489-504. 

Demmig, B. Bjorkman, O. (1987). Comparison of the effect of excessive light on chlorophyll fluorescence (77 K) and photon yield of O2 evolution in leaves of higher plants. Planta, 171,171-84. 

Fig. 5 Linear absorption (1, 2) and one-photon-excited fluorescence (1, 2 ) for the quantum yield standard Cresyl Violet (1, 1 ) and the proposed standard PD 2631 (2, 2 ) for NIR wavelengths. Molecular structures are shown to the left...

Radiationless transitions have an associated rate constant (/ radiationless) intcrsystcm crossings have a corresponding rate constant (/ crossing) and fluorescence is characterized by its own rate constant, designated here as / fluorescence [Each of these competing events are first-order relaxation processes. See Chemical Kinetics (9. Relaxation Kinetics)] A photo-excited molecule rarely re-emits every photon by fluorescence, and the quantum yield is the ratio of the number of photons produced by fluorescence to the number of photons originally absorbed. Accordingly, the quantum yield (f) is formally... 

The regions in which PuFe shows continuous absorption as well as the 5f state energies shown in Figure 1 are based primarily on Steindler and Gunther s measurements (16). For a current theoretical interpretation of the 5f state structure of PuFe see J. Blaise et al. (this volume). The first dissociation limit of PuFe is crudely estimated based on the extremely small PuFe gas fluorescence photon yield but long fluorescence lifetime we have found (see below). In addition, the fact that PuFe is a better fluorinating agent than molecular fluorine... 

Two-photon excited fluorescence (TPEF) is one of the most useful ways to quantify TPA in optical materials competing with nonlinear absorption. While nonlinear transmission yields absolute quantities describing TPA, TPEF requires knowledge of the collection efficiency if absolute data must be acquired. Thus, the use of standards is the method of choice to determine 5 in case of TPEF. 

TABLE 3.5 Compilation of Extinction Coefficient ( ), Change of State Dipole Moment (A/j01), Maximum for Two-Photon Excitation (/n), Two-Photon Absorption Cross Section (5) at >TP, Maximum for One-Photon Absorption Fluorescence Quantum Yield ( f), and the... 

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