photolysis

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photolysis

 [fo-tol´ĭ-sis]
chemical decomposition or change by the action of light or other radiant energy. adj., adj photolyt´ic.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

pho·tol·y·sis

(fō-tol'i-sis),
Decomposition of a chemical compound or cleavage of a chemical bond by the action of light.
[photo- + G. lysis, dissolution]
Farlex Partner Medical Dictionary © Farlex 2012

pho·tol·y·sis

(fō-tol'i-sis)
Decomposition of a chemical compound by the action of light.
[photo- + G. lysis, dissolution]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

photolysis

chemical decomposition using light energy (‘splitting by light’). In 1933, Cornelius van Niel proposed that the initial step in PHOTOSYNTHESIS was the photolysis of water, leading to the release of oxygen ions (forming oxygen gas) and hydrogen ions which were involved in the reduction of NADP during the LIGHT REACTIONS. Recently it has become more common to explain the breakdown of water as a ‘separation of charge’, a fast spontaneous ionic reaction with water splitting into hydrogen (H+) and hydroxl (OH-) ions. The end result is the same as photolysis, but light is not thought to be involved in the process.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
References in periodicals archive ?
Freed, "Quantum theory of photodissociation of polyatomic molecules: application to HCN," Chemical Physics Letters, vol.
Dixon, "Photodissociation of H2O at 121.6 nm: A state-to-state dynamical picture," J.
At 193 nm, and in single-photon processes, the photodissociation proceeds according to the following two-channel scheme:
Assuming that methane-to-ethane photo-chemistry occurs at these distances from the Sun, the primary photodissociation mode in light with wavelengths between 129 to 147 nm (the methane absorption band) is the elimination of molecular hydrogen and the formation of a divalent carbon called methylene.
Since O([sup.1][D.sub.2]) is the primary photodissociation product of stratospheric ozone, [O.sub.3] + hv [right arrow] O([sup.1][D.sub.2]) + [O.sub.2]([sup.1][[DELTA].sub.g]), the O([sup.1][D.sub.2]) reaction is of great interest for atmospheric chemistry.
Kumar, "Photodissociation effects on pulsed laser deposited silver oxide thin films: surface-enhanced resonance Raman scattering," Journal of Raman Spectroscopy, vol.
Ostrovskii, Interference of electrons resulting from photodissociation of an atom in electric field, JETP Lett.34, 403-405(1981).
(2) Water vapour may be increased at times by this mechanism but as water vapour is at a higher concentration during northern summer months, it appears that water vapour formation may more than compensate for that lost by photodissociation.
Radicals R are produced by photodissociation of the initator DMPA.
The negative correlation between [O.sub.3] and [NO.sub.2] is in keeping with the process of nitric oxide scavenging [O.sub.3] in the atmosphere and the photodissociation of [NO.sub.2] to nitric oxide and [O.sub.3] (Beaney and Gough 2002).