Photolysis short-wave

Solar energy with the short wave length range and long wave range can be utilized by photolysis and by pyrolysis, respectively. As for photolysis, we have (1) the biological area based upon the photosynthesis, and (2) the electrochemical area such as photoelectrochemical with photo semiconductor, with dye and metal complex etc. [13],... 

A recent study by Ward on the photolysis of o-xylene in the vacuum ultraviolet (1600-2100 A) and at 2537 A has confirmed the observations of Wilzbach and Kaplan. Benzene, toluene, ethylbenzene, m- and p-xylene and o- and m-ethyltoluene were found in much the same proportions. Furthermore the product distribution was not altered substantially at the short wave lengths. The dimer o,o -dimethylbibenzyl was observed. A new product which was observed only in the vacuum ultraviolet photolysis was benzocyclobutene from isotopic studies this product was shown to arise from the loss of a single hydrogen atom from each of the methyl groups of o-xylene. 

Photolysis of l-methylnaphtho[l,8-rfe]-l,2,3-triazine (23) afforded the biradical 24 which could be trapped by hydrogen, benzene or vinyl bromide.7 Photolysis of the 2-methyl isomer 25 gave the triaziridine 26 in a two-photon laser process at 10-85 K. Short-wave photolysis of 25 yielded 26 and naphtho[l,8-af]pyrazole (27).339... 

The photolysis beam was the output from a UVP Inc. model UVG-54 short wave UV-254 nm lamp. All photolysis experiments were performed in air. Light intensity measurements were made using an International Light IL 1350 radiometer. 

Just as in Faraday s law the amount of electrolysis is proportional to the current passed through an electrolytic cell, so in Grotthus law, the amount of photolysis is proportional to the absorbed energy of short enough wave-length to start chemical action. The departures from apparent proportionality can be explained in a similar way, the former by the phenomenon of residual currents or polarization, the latter, as shown by- P. Villard, by the existence of a limiting low exposure... 

The detection of short-lived transient species is often achieved by flash photolysis where an extremely short flash of UV/Vis radiation from a laser generates a high concentration of transient species, and a second probe beam monitors any changes that occur after the flash. Traditionally, UVA is spectroscopy has been used as a detection method. However, time-resolved infrared spectroscopy (TRIR), a combination of UV flash photolysis and fast IR detection, also has a long history. There are several different approaches to fast IR spectroscopy and the method of choice depends upon the timescale of the reaction. Measurements on the nanosecond to millisecond timescale are obtained using point-by-point techniques or by step-scan FTIR. In the point-by-point approach, a continuous wave IR laser (GO or diode) or globar is used as the IR source, which is tuned to one particular IR frequency (Figure 3). ... 

It is possible to tune the laser wavelength very rapidly over a spectral region where molecular absorption lines have to be detected. With electro-optical components, for instance, pulsed dye lasers can be tuned over several wave numbers within a microsecond. This opens new perspectives for spectroscopic investigations of short-lived intermediate radicals in chemical reactions. The capabilities of classical flash photolysis may be considerable extended using such rapidly tunable laser sources. 

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