Absorption of light energy

A number of electronic and photochemical processes occur following band gap excitation of a semiconductor. Figure 5 illustrates a sequence of photochemical and photophysical events and the possible redox reactions which might occur at the surface of the SC particle in contact with a solution. Absorption of light energy greater than or equal to the band gap of the semiconductor results in a shift of electrons from the valence band (VB) to... 

What molecular architecture couples the absorption of light energy to rapid electron-transfer events, in turn coupling these e transfers to proton translocations so that ATP synthesis is possible Part of the answer to this question lies in the membrane-associated nature of the photosystems. Membrane proteins have been difficult to study due to their insolubility in the usual aqueous solvents employed in protein biochemistry. A major breakthrough occurred in 1984 when Johann Deisenhofer, Hartmut Michel, and Robert Huber reported the first X-ray crystallographic analysis of a membrane protein. To the great benefit of photosynthesis research, this protein was the reaction center from the photosynthetic purple bacterium Rhodopseudomonas viridis. This research earned these three scientists the 1984 Nobel Prize in chemistry. 

Photochemical solvolysis reactions are directly analogous to ordinary solvolysis reactions except that the absorption of light energy is necessary for reaction to occur ... 

An alternative approach to homolytic cleavage is photolysis, the absorption of light energy, especially... 

Absorption of light energy causes an electron to be excited from the valence band to the conductivity band. This electron and the electron hole are mobile, and can move on the surface of the solid where they take part in redox reactions. 

In the following, the second term in Eq. (4) is discussed on the basis of a balance of absorption of light energy and heat dissipation. To determine the temperature increment, it is necessary to estimate absorption of light energy, heat dissipation, heat capacity of the gel, and thermal diffusion velocity. Accord-... 

Absorption of light energy in the near-ir-visible-near-uv region by a finely powdered sample is measured from light reflected back off a powder surface... 

When light is absorbed by a molecule, a transition to a higher electronic state takes place and this absorption is highly specific for the molecules concerned radiation of a particular wavelength or energy is only absorbed by a particular molecular structure. If electrons are raised, due to absorption of light energy, to an upper... 

Infrared spectroscopy The measurement of the absorption of light energy, in infrared light, of a tiny scraping taken from a specimen, to determine its nature or origin. 

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