FLASH PHOTOLYSIS AND PULSE RADIOLYSIS

Guldi D M 1997 Capped fullerenes stabilization of water-soluble fullerene monomers as studied by flash photolysis and pulse radiolysis J. Phys. Chem. A 101 3895-900... 

Some of the most important questions one can ask in the study of kinetics concern the rates of reactions of the intermediates. In some cases, values can be obtained by direct experiments. For example, one might generate the intermediate by an independent method capable of producing it much more rapidly than it reacts. Then it can be examined in its own right. Chapter 11 presents methods for doing so, such as flash photolysis and pulse radiolysis. 

Some of the most conclusive studies of the mechanisms of chain reactions come from experiments in which some of the propagating steps have been independently measured directly. This measurement can sometimes be done by the use of flash photolysis and pulse radiolysis (Chapter 11). Such determinations can verify the occurrence of a certain reaction in the sequence and provide its rate constant. 

The optical absorption spectra of sulfonyl radicals have been measured by using modulation spectroscopy s, flash photolysis and pulse radiolysis s techniques. These spectra show broad absorption bands in the 280-600 nm region, with well-defined maxima at ca. 340 nm. All the available data are summarized in Table 3. Multiple Scattering X, calculations s successfully reproduce the experimental UV-visible spectra of MeSO 2 and PhSO 2 radicals, indicating that the most important transition observed in this region is due to transfer of electrons from the lone pair orbitals of the oxygen atoms to... 

Flash Photolysis and Pulse Radiolysis Studies Non-linear Optical Effects 142... 

Much of the achieved advances result from the development and availability of instrumentation to study slow and fast reactions at pressures up to 300 MPa, including stopped-flow, T-jump, P-jump, NMR, ESR, flash-photolysis, and pulse-radiolysis instrumentation (1, 2, 4, 6, 7). Readers are advised to consult the quoted references for more detailed information, since these present a detailed account of the present instrumentation and commercial availability of such equipment. 

Flash photolysis and pulse radiolysis techniques have been developed to study Fe Ru ET in Ru-modified proteins [21,26,27]. A method that allows study of electron transfer from a surfaee ajRu(IIIXhistidine) to a protein redox center is outlined in the Scheme [21]. The ET reaction is initiated by photogenerated... 

Epr is most effective for detecting free radicals that may occur as intermediates in oxidation and reduction reactions involving transition metal ions. Since these transients are invariably quite labile, epr is combined with continuous flow, (more conveniently) stopped-flow, flash photolysis, and pulse radiolysis. 

Behar, D., G. Czapski, and I. Duchovny, Carbonate Radical in Flash Photolysis and Pulse Radiolysis of Aqueous Carbonate Solutions, J. Phys. Chem., 74, 2206-2210 (1970). 

R. V. Bensasson, E. J. Land, and T. G. Tmscott, Flash Photolysis and Pulse Radiolysis, Pergamon Press, 1983. 

The lifetime of the RSSR radical anions is usually very short on the microsecond timescale in water. However, they have been detected and characterized by time-resolved optical methods. In one early study, y irradiation of matrices containing alkyl and aryl disulfides provided spectroscopic evidence for the formation of the corresponding radical anions. Subsequently, the formation of RSSR radical anions has been well documented, particularly by EPR, flash photolysis, and pulse radiolysis. In fact, 2a/ a three-electron bonded radical anion species, particularly from sulfur compounds, constitute significant and interesting intermediates. The RSSR radical anions may be obtained from different approaches. One is by one-electron reduction of disulfides (equation 75), such as by pulse radiolysis. However, the most common approach is by association of RS and RS (equation 79). ... 

Janata E (1992b) Instrumentation of kinetic spectroscopy. 10. A modular data acquisition system for laser flash photolysis and pulse radiolysis experiments. Radiat Phys Chem 40 437-443 Janata E, Lilie J, Martin M (1993) Instrumentation of kinetic spectroscopy. 11. An apparatus for AC-conductivity measurements in laser flash photolysis and pulse radiolysis experiments. Radiat Phys Chem 43 353-356... 

Nasr, C. Vinodgopal, K. Hotchandani, S. Kamat, P. V. Excited state and reduced forms of a textile diazo dye, Naphthol blue black. Spectral characterization using laser flash photolysis and pulse radiolysis. Radiat. Phys. Chem. 1997, 49, 159. 

Janata E. (1992) Instrumentation of kinetic spectroscopy-7. A precision integrator for measuring the excitation in laser flash photolysis and pulse radiolysis experiments. Radiat Phys Chem 39 315-317. 

Bensasson RV, Land EJ, Truscott TG. (1983) Flash Photolysis and Pulse Radiolysis, Contributions to the Chemistry of Biology and Medicine. Pergamon Press, London. 

Triplet, radical anion, and radical cation spectra of furocoumarins have been determined by flash photolysis and pulse radiolysis. Triplet spectra are modified by hydrogen bonding and in water the triplets may be regarded as exciplexes. " The triplet states, semi-oxidized and semi-reduced radicals of haematoporphyrin, and three O-acyl derivatives have also been characterized. Triplet-state participation of several 4-hydroxy- and 4-methoxybenzothiazoles has been studied by flash photolysis. " These compounds are models for pheomelonin. 

Pulsed Radiation Techniques Flash Photolysis and Pulse Radiolysis . R.V. Bensasson, E.J. Land, T.G. Truscott, Excited States and Free Radicals in Biology and Medicine Contributions from Flash Photolysis and Pulse Radiolysis, Oxford University Press, Oxford, 1993, Chap. 3, pp. 64-100. 

More complete information on photochemical and concomitant processes occurring in the [Co(sep)]3+...r and [Co(sep)]3+...Br systems was obtained from flash photolysis and pulse radiolysis data [300],... 

Ferradini and Bensasson have reviewed flash photolysis and pulse radiolysis as tools for studying the kinetic and... 

Serpone N. and Pelizzetti E. (1986), Fundamental studies into the primary events in photocatalysis employing CdS and Ti02 semiconductors. Photoluminescence, laser flash photolysis, and pulse radiolysis , in Homogeneous and Heterogeneous Photocatalysis, Pelizzetti E. and Serpone N., eds., Reidel Publ. Co., Dordrecht, The Netherlands, pp. 51-90. 

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