Photo-sensitivity

Dougherty, T. J. Methods in Porphyrin Photo-sensitization, Kessel, D., Ed, Pleunum New York, 1985 p 313. 

Various names for this allotropes were in use intermediate phase sulfur (ip-S) [184], high-pressure unknown phase (HPU phase) [191], and photo-sensitive or, more recently, photo-induced sulfur (p-S) [57, 58, 119, 186], respectively. We are inchned to make use of the term photo-induced since it has clearly turned out that the formation of this allotrope is induced when employing laser light of suitable power density and wavelength [1]... 

Baum AA, Kamischky LA, McLeod Jr D, Kasai PH (1973) Mercury photo-sensitized oxidation of primary and secondary aliphatic amines J Am Chem Soc 95(2) 617-618... 

Consequently conventional antioxidant mechanisms must be expected to protect against photo-oxidation. Thus hydroperoxide decomposition to inert molecular products will reduce the rate of photoinitiation and scavenging of any of the free radical species will be beneficial, although the effectiveness of conventional antioxidants in photo-oxidations is limited by their own stability and the photo-sensitizing propensity of their products (3,). 

This material, normally supplied or stored in sealed ampoules and used as a paper chromatography spray reagent, is photo-sensitive. Exposure to UV light causes exothermic decomposition to acetone and chloromethane. Ampoules have burst because of pressure build-up after exposure to fluorescent or direct day light. Store cool and dark, and open ampoules with personal protection. The material also reacts violently with rubber [1,2], It should not be heated to above its boiling point [3], There is also a preparative hazard. 

Although there are a number of photo-sensitive coupling chemistries that have been used in modification and conjugation reactions (Chapter 2, Section 7), it has been primarily aryl azides... 

Kamat, PV., Fox, M.A. 1983. Photo-sensitization of TiO, colloids by Erythrosin-B in acetonitrile. Chem Phys Lett 102 379-384. 

The latest addition to this list of dry developing resist materials is a contribution from IBM s San Jose Research Laboratory (66-67) that evolved from efforts to design positive-tone resist materials that incorporate chemical amplification. These efforts were stimulated by the fact that the quantum yield of typical diazoquinones of the sort used in the formulation of positive photoresists is 0.2 to 0.3 thus, three or four photons are required to transform a single molecule of sensitizer. This places a fundamental limit on the photo-sensitivity of such systems. 

A rapid reaction technique for analyzing the kinetics of photo-sensitive or photo-responding biochemical reactions. One application deals with the determination of... 

Flash photolysis techniques are described, the reaction products being observed in both emission and absorption with resolution times of about a ftsec. Some results with C2H2—O mixts photo sensitized with NO2 are given... 

Light emitted from flashrini dated explns of acetylene and 0 photo sensitized by N02 in a large quartz tube was studied photo-electricaLly. Presence of very short-lived Intense emission from the diat radicals was confirmed. Although main part of expln is homogeneous, 2 deton waves travel a short distance to the ends of the reaction vessel. Sharp peak is caused by the impact of one of these deton waves on the vessel window nearer the spectrograph Ref 5.A. Thrush, ProcRoySoc (London)... 

Abstract Optical techniques for three-dimensional micro- and nanostructuring of transparent and photo-sensitive materials are reviewed with emphasis on methods of manipulation of the optical field, such as beam focusing, the use of ultrashort pulses, and plasmonic and near-field effects. The linear and nonlinear optical response of materials to classical optical fields as well as exploitation of the advantages of quantum lithography are discussed. 

Figure 1. Photo-oxidation of azoalkanes and mercury-photo-sensitized oxidation of alkanes...

Vanadium pentoxide becomes markedly photo-sensitive when immersed in glycerol, benzaldehyde, cinnamic aldehyde, cuminol, or aqueous mannitol solution, and exposed to light. It blackens and undergoes reduction, giving rise, initially, to hypovanadic oxide, VOg. With aqueous solutions of citric acid or tartaric acid carbon dioxide is evolved during the change.9... 

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