Energy level diagram chlorophyll

Fig. 2. Energy level diagram of rose bengal, chlorophyll, and anthracene in solution...

Figure 4-9. Energy level diagram indicating the principal electronic states and some of the transitions of chlorophyll. Straight vertical lines represent the absorption of light wavy lines indicate radiationless transitions, for which the energy is eventually released as heat and broken lines indicate those deexcitations accompanied by radiation. In the literature, for chlorophyll is also referred to as S0, as Slt S H as S2, and T sfj as Tt (similar symbols occur for carotenoids).

The primary processes of photochemistry involve the light absorption event, which we have already discussed, together with the subsequent deexcitation reactions. We can portray such transitions on an energy level diagram, as in Figure 4-9 for chlorophyll. In this section we discuss the various deexcitation processes, including a consideration of their rate constants and lifetimes. 

Figure 5-7. Energy level diagram including vibrational sublevels, indicating the principal electronic states and some of the transitions for carotenoids. The three straight vertical lines represent the three absorption bands observed in absorption spectra, the wavy lines indicate possible radiationless transitions, and the broad arrows indicate deexcitation processes (see Fig. 4-9 for an analogous diagram for chlorophyll).

Fig. 4. (A) Scheme of possible molecular arrangement of a chloroplast extract membrane containing chlorophyll, carotenoid and phospholipid as essential components. Ch, chromophore portion of chlorophyll Pht, phytol tail of chlorophyll C, carotenoids P, phospholipid. (B) The corresponding energy barrier diagram for the membrane (M)-water (W) system. The broken line in the membrane represents the reduced energy barrier level due to carotene. The solid lines in the potential wells represent the ground and first excited states of chlorophyll. The dotted line at the right of the membrane solution energy barrier represents the lowering of the energy barrier due to excited biliprotein (phy-cocyanin). The 4 A width is the distance of closest approach between the redox species in water and the chromophore in the membrane.

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