Light energy absorbance

The Fate of Light Energy Absorbed by Photosynthetic Pigments... 

Each photon represents a quantum of light energy. A quantum of light energy absorbed by a photosynthetic pigment has four possible fates (Figure 22.8) ... 

FIGURE 22.8 Possible fates of the quantum of light energy absorbed by photosynthetic pig-men ts. 

It is possible for homolysis to occur when the light energy absorbed by a molecule reaches or exceeds the bonding energy. Radicals are formed or, in the case of halogens, atomic halogen ... 

Johns would like to restrict the term exposure to the measure of incident light energy, and the term dose to the measure of light energy absorbed.11... 

Figure 15. Optoacoustic action spectrum of the heat release (ot, A—A) from the P (64 k Da) and r700 states, relative to the light energy absorbed by Pr (calibration with CuCl2 (..)). (Spec-... 

The formed free atoms absorb the light at a characteristic wavelength from a hollow cathode lamp that is positioned on one side of the flame. A spectrophotometer with a grating monochromator located on the other side of the flame measures the intensity of the light beam. Because absorption is proportional to the number of free atoms that are produced in the flame, the light energy absorbed by the flame is a measure of the element s concentration. The FLAA technique is relatively free of interelement spectral interferences, but it has the sensitivity that is inferior to ICP-AES or GFAA. 

The most basic design requirements of the bacterial photosynthetic reaction centers then, are a light energy absorbing center and two chains of redox centers that connect this light-activatable center to cytochrome c and quinone on opposite sides of the membrane. The physical process by which electrons are transferred between members of the chains in reaction centers, and indeed in the vast majority of electron transfer proteins, was also revealed by Chance, together with Devault, in these same years [4]. 

In each of these cases, the thickness of the coating film is very important (inks 2 to 10 microns versus a fluid coating of 0.5 to 2 mils) on the amount of light energy absorbed by the photoinitiator. The amount of pigment, dispersion, and reflectance of the paint film are also Important for light absorption by the photocatalyst. 

Photosynthesis. A metabolic process in plants and certain bacteria, using light energy absorbed by chlorophyll and other photosynthetic pigments for the reduction of C02, followed by the formation of organic compounds... 

Figure 19.28 Energy transfer from accessory pigments to reaction centers. Light energy absorbed by accessory chlorophyll molecules or other pigments can be transferred to reaction centers, where it drives photo induced charge separation. The green squares represent accessory chlorophyll molecules and the red squares represent carotenoid molecules the white squares designate protein.

The light energy absorbed by chromophores causes electrons to move to higher energy levels. In photosynthesis energy absorption is used to drive electron flow. 

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