Triplet state energy level diagram

Jablonski (48-49) developed a theory in 1935 in which he presented the now standard Jablonski diagram" of singlet and triplet state energy levels that is used to explain excitation and emission processes in luminescence. He also related the fluorescence lifetimes of the perpendicular and parallel polarization components of emission to the fluorophore emission lifetime and rate of rotation. In the same year, Szymanowski (50) measured apparent lifetimes for the perpendicular and parallel polarization components of fluorescein in viscous solutions with a phase fluorometer. It was shown later by Spencer and Weber (51) that phase shift methods do not give correct values for polarized lifetimes because the theory does not include the dependence on modulation frequency. 

Figure 9.18 shows a typical energy level diagram of a dye molecule including the lowest electronic states Sq, and S2 in the singlet manifold and and T2 in the triplet manifold. Associated with each of these states are vibrational and rotational sub-levels broadened to such an extent in the liquid that they form a continuum. As a result the absorption spectrum, such as that in Figure 9.17, is typical of a liquid phase spectrum showing almost no structure within the band system. 

Fig. 1. Schematic energy-level diagram for a dye molecule. Electronic states Sq = ground singlet state = first excited singlet state S2 = second excited singlet state Tj = first excited triplet state T2 = second excited triplet state EVS = excited vibrational states. Transitions A = absorption excited states ...

Figure 6.3 Energy level diagram for the triplet state of naphthalene (D = 0.1003 cm-1, E= -0.0137 cm-1, g = 2.003). Solid lines correspond to orientation of the magnetic field along the z-axis, dashed lines for orientation along the x-axis. Arrows show the allowed transitions for 9.50 GHz microwave radiation.

Fig. 13 Qualitative molecular orbital energy level diagram of the dimer d orbitals with the 14 electrons showing the electronic configuration 525 27i47i 4o2 (singlet) and the first excited state 828 2it4it 4a1CT 1 (triplet)...

Figure 4. Electronic energy level diagram for anthracene illustrating the photophysical transitions (including reaction with the initiator from both the singlet and triplet states) and the associated kinetic constants.

Fig. 8 Energy level diagrams for the dansyl units of dendrimer 11 and the investigated lanthanide ions. The position of the triplet excited state of 11 is uncertain because no phosphorescence can he observed...

Figure 1.2. Jablonski energy level diagram showing the singlet state and the triplet state with its zero-field splittings for a planar aromatic chromophore.

Fig. 3. Schematic energy level diagram illustrative of use of an intermediate for crossover from triplet to ground state,92-93...

Figure 4 Energy level diagram for an octahedral NiA6 chromophore. Full lines refer to triplet states, broken lines to singlet states. The free ion parentage is shown on the left side, (a) The effect of varying ea (e = 0 cm-1) (b) the effect of varying e jea ea = 3000 cm-1) (c) the effect of varying g (see text e = 3000 cm-1, e = 0 cm-1)...

FIGURE 4. Energy level diagram for the trans-stilbene locally excited singlet and triplet states, the trans-stilbene-fumaronitrile (FN) exciplex, and triplet fumaronitrile. 

Figure 3.8 Tanabe-Sugano energy level diagram for a 3d6 ion in an octahedral crystal field. Note that some of the highest energy triplet and singlet crystal field states listed in table 3.3 are not shown in the diagram.

Fig. 1. Schematic energy level diagram for fluorescence and dissociation of some polyatomic molecules. A0 to X are vibration levels of the normal electronic state. Y to Y are the vibration levels of the electronic (singlet) state formed by absorption. Zo to Zm are vibration levels of the long lived (triplet) electronic state. Fluorescence occurs by transition to X levels from F0 to Za. Dissociation is possible at higher energies than D (Noyes98).

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