photochemical reactions


Also found in: Wikipedia.

photochemical reactions

Chemical reactions which are initiated by a particular wavelength of light.
Dictionary of Unfamiliar Words by Diagram Group Copyright © 2008 by Diagram Visual Information Limited
References in periodicals archive ?
Instead, it's all based on photochemical reactions - light.
The initial fluorescence explains the fluorescence emission when the primary electron acceptor quinone (QA) of photosystem II (PSII) is fully oxidized and the reaction center (P680) is open, indicating the activation of the photochemical reactions (Baker & Rosenqvst, 2004).
Description: The "VOC" directive that aims to reduce ozone formation potential of VOCs in connection with photochemical reactions in ambient air, defines 12 sub-categories for coating products applied to buildings and five subcategories for vehicle refinishing products for which limits are set with regard to VOC content.
Photochemical reactions are chemical reactions in which energetic photons from ultraviolet solar radiation break chemical bonds in the atmosphere oxygen molecules (O2) to produce O atoms as well as other ions.
Photochemical smog was derived from coal emissions, vehicular emissions, industrial emissions, forest and agricultural fires and photochemical reactions of these emissions, he said.
The NPQ also characterizes a protective mechanism of the plant to dissipate the excessive radiant energy not used in the photochemical reactions (Silva et al., 2011), but, in this case, acting by decreasing the excitation pressure of PSII, which provides protection against damages in the photosynthetic apparatus, such as electron transport dependent and/or triplet chlorophyll dependent photo damage (Vass, 2012).
Thus, the rate of O2 evolution can indicate the activity of photochemical reactions and electron transport in PSII.
Despite the fact that Titan has been located much further from the Sun than the Earth and that radiation flux coming from the Sun to the moon was 100 times less, the intensity of UV rays was enough to spur photochemical reactions in the upper layers of Titan's atmosphere.
And just as chemists have sought the underlying mechanisms responsible for thermochemical or photochemical reactions, their efforts are dedicated to unravelling the mysteries of mechanical action.

Full browser ?