Phosphorescence relative positions

Fig. 3.1. Perrin-Jablonski diagram and illustration of the relative positions of absorption, fluorescence and phosphorescence spectra.

FIGURE 7. Relative positions of absorption, fluorescence, and phosphorescence The 0-0 peak is common to both absorption and fluorescence spectra (see Fig. 6). ISC, Intersystem crossing. (Modified from Ref. 2.)... 

FIGURE 1. Jablonski diagram for the relative positions of the electronic energy levels of a molecule, where F = fluorescence rate, P = phosphorescence rate and VR = vihrational relaxation... 

The relative position of the excited states of benzophenone (10) is shown in Figure 5.13a. Intersystem crossing leads from a (n, r ) state to a state this type of transition is favored by spin-orbit coupling to such an extent that st and no fluorescence is observed. If, however, S and T, are (n,7T ) states and are disposed as in Figure 5.13b, d>sr is so small that practically no phosphorescence can be observed although the molecule has n- jr transitions. The relative disposition of (n,Ji ) and states may... 

Fig. 4. Relative position of lower excited singlet state (S,), triplet state (Tt) and metal ions (Mi), electronic levels, and transitions between them in metal ion complexes with organic ligands, (A) luminescence (fluorescence and phosphorescence) with levels of metal ion located above Sr levels, (B) phosphorescence with metal ion levels located between S,- and Trlevels, (C) sensitized (native) luminescence with metal ion levels located below Ti-levels...

Nuclear magnetic resonance spectroscopy is a technique that, based on the magnetic properties of nuclei, reveals information on the position of specific atoms within molecules. Other spectroscopic methods are based on the detection of fluorescence and phosphorescence (forms of light emission due to the selective excitation of atoms by previously absorbed electromagnetic radiation, rather than to the temperature of the emitter) to unveil information about the nature and the relative amount specific atoms in matter. 

Figure 14. Absorption spectrum (top) and fluorescence excitation spectrum (middle) of isoquinoline vapor at room temperature, and the excitation spectrum of biacetyl phosphorescence (bottom), sensitized by energy transfer from the triplet isoquinoline. The band positions (in cmT1) are relative to the starred 0+ band at 31,925cm-1. (From ref. [45] with permission.)...

Halogen substitution in the 1-position of naphthalene has a dramatic effect on some, but not all, of the optical and magnetic properties of the lowest triplet state. There is considerably more vibronic activity in the phosphorescence spectra of the halonaphthalenes, especially in IIN, but the positions of the (0,0) bands are relatively unchanged across the series. For all molecules studied, the total decay constants are in the ratio kj,>ky> k but these are... 

In the phosphorescence spectra of AQ-2S in Fig. 2a, the spectra 4 and 5 are different from the spectrum 2 in the above-mentioned relative intensity of the 0-0 peak and sharpness. The spectrum 5 is at longer wavelengths by 320 cm l and a little sharper than the spectnim 4 which is at almost the same position as the spectrum 1. The excitation spectra in Fig. 2b correspond to the mr absorption spectra. In Fig. 2b the spectra 4 and 5 are sharper than the spectrum 2,and the spectrum 5 is at longer wavelengths by 420 cm and sharper than the spectrum 4 which is at almost the same position as the spectrum 2. The spectrum 2 is at almost the same position as that corresponding to the spectrum 1 in Fig. 2a. From these results, AQ-2S is concluded to form complexes with g- and Y CD s, and is in surroundings more hydrophobic in the Y CD complex than in the g-CD complex. The structures of the CD-AQ-2S complexes shown in Fig. 3 are thought to be most probable, in consideration of the quinone dimensions in Fig. la, the inner diameters of the CD s, and the results obtained by other authors [2,8]. 

As is seen in Fig. 7, in the three AQ sulfonates, the phosphorescence spectra are sharper and the relative intensities of the 0-0 peak are weaker in the presence of dimethyl g-CD than in the presence of g-CD, but the phosphorescence spectra are at almost the same position in both cases. From these results the structures of the dimethyl... 

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