Radiation Chemistry Of Water Research Articles

Effects of early track structure on the radiation chemistry of water irradiated with heavy ions

The ways in which the physical structure of heavy ion tracks influences the observed radiation chemistry of water are reviewed. Hydrated electrons are produced in the same initial yield as in low LET radiolysis, but they disappear more rapidly during diffusion of the denser tracks. LET increases with increased charge and with decreased ion velocity, but radii of the core and penumbra regions of the track depend only on ion velocity. Consequently, radicals can be produced at very different spatial densities with ions of similar LET. Homogeneous radical, molecular and initial total water decomposition yields reflect these differences. The HO 2 radical is produced in significant yield only in tracks, but unlike e - aq and OH its yield appears to be a unique function of core LET. Radical scavengers increase the effective radical yields by competing with recombination processes, most efficiently in the denser tracks. Nuclear fragmentation is expected to increase radical yields measured at depth in thick targets irradiated with high energy heavy ions, by contaminating the beam with secondaries that have less dense tracks. Recent evidence indicates that this effect may not be as large as had been thought previously.

Primary processes in the radiation chemistry of water

Insights into the primary processes of water radiation chemistry developed fairly recently are reviewed, with particular emphasis on time-resolved experiments performed at Argonne National Laboratory. Properties and reactivity of the three important species H atom, solvated electron, and “dry” or presolvated electron are reviewed first, followed by a discussion of the role of water excited states and the process of electron solvation. Finally, nonhomogeneous spur processes are discussed, including the role of spin-dependent radical chemistry and the initial distance distribution of the (e -)aq ion.

Radiolysis Aspects of the Aqueous Self-Cooled Blanket Concept and the Problem of Tritium Extraction

In the Aqueous Self-Cooled Blanket (ASCB) concept, an aqueous 6Li solution in a metallic structure is used as a fusion reactor shielding-breeding blanket. Radiolysis effects could be very important for the design and the use of an ASCB. Although many aspects of the radiation chemistry of water and dilute aqueous solutions are now reasonably well understood, it is not possible to predict the radiochemical behaviour of the concentrated candidate ASCB solutions quantitatively. However, by means of a worst case calculation for a possible ASCB for the Next European Torus (NET) it is shown that even with an important rate of water decomposition the ASCB concept is still workable. Gas bubbles and explosive mixtures can be avoided by increasing the pressure in the neutron irradiated zone and by extracting and/or recombining the radiolytically produced hydrogen and oxygen. This could require an additional inert gas loop, which could also be used as part of the tritium extraction installation.

Sodium-water clusters and their role in radiation chemistry

Studies of sodium-water clusters are presented which could serve as models for the recently suggested intermediate species in the radiation chemistry of water. The ionization potentials and the lower excited states of sodium with n-water molecules are calculated by ab initio quantum chemistry methods. The ionization potential calculated at the SCF level for the water monomer is 4.10 eV, which becomes 4.34 at the MP2 correlation level. The experimental value is 4.379 ± 0.002 eV. Structural data is presented for the lower members of the sodium with n-water clusters. In addition the Hartree-Fock calculations indicate that there should be some strong charge transfer to solvent transitions at higher energies.

Radiation-induced organic hydrogen isotope exchange reactions in aqueous solution

A study of the possible radiation-induced exchange reactions of organic hydrogen isotopes in which there is no net chemical change is reported. The present day ideas regarding the radiation chemistry of water according to which the energy from ionizing radiation is deposited in regions called ''spurs'' are reviewed. Isotope exchange processes for benzene and other aromatic compounds are discussed in light of their involvement with the radiolysis products of water, hydrogen atoms, solvated electrons, and hydroxyl radicals. The involvement of metal ions in the isotope exchange was also surveyed. It is concluded that the radiation-identity reactions of the aromatics with a radiolysis product involves one oxidation step and one reduction step. The various steps are summarized in tabular form. The isotope exchange reactions are expected to take place in more complex molecules, and these radiation-induced hydrogen exchange reactions merit consideration in discussions of radiobiological processes. 40 references are cited.

Book Review: The Radiation Chemistry of Water. By I. G. Draganić and Z. D. Draganić

Book Review: The Radiation Chemistry of Water. By I. G. Draganić and Z. D. Draganić

The Radiation Chemistry of Water

The Radiation Chemistry of Water

The radiation chemistry of water (Draganic, Ivan G.; Draganic, Zorica D.)

The radiation chemistry of water (Draganic, Ivan G.; Draganic, Zorica D.)

The Radiation Chemistry of Water

The Radiation Chemistry of Water

The radiation induced reactions of aqueous polyethylene oxide solutions. IV. Effect of additives as selective scavengers

AbstractIt was found that the effect of additives on the radiation induced reactions of aqueous polyethylene oxide solutions cannot be explained solely on the basis of competition between polymer and additive for hydrogen abstracting radicals. Polymer‐solvent and polymer‐additive interactions were found to be important. Some systems studied were best described in terms of the effect of additive on the radiation chemistry of water and the action of products of additive‐radical reactions on the polymer. Additives capable of influencing the ratio of intra to intermolecular crosslinking produced marked effects. The results indicate that polyethylene oxide is very reactive toward the hydroxyl radical, less so toward the hydrogen atom, and relatively inactive toward the solvated electron, although solvated electron scavengers increase the dose required to gel.

Solvated Electron Formed in Water by the Silent Electric Discharge in Argon Atmosphere

Abstract Based on radiation chemistry of water a study on the chemical changes resulting from the silent electric discharge of aqueous solution under argon atmosphere was made for the purpose of elucidating the nature of the reducing species formed. In the neutral aqueous ClCH2COOH system the effects of such additives as CH3OH and NO3− on the yield of Cl− and in the system containing NO3− the yield of NO2− were investigated. Moreover, in the alkaline aqueous K3Fe-(CN)6 system emphasis was placed on the yield of aquocomplex. In view of the non-dependence of the yield of Cl− on the concentration of additive NO3− and of the low yields of NO2− and Fe(CN)5OH23− produced, it was concluded that in the silent electric discharge the yield of solvated electrons which react with solutes in the bulk of water is very small (G\lesssim0.06). Reasons for the low yield of solvated electrons are briefly described.

Reaction Mechanism Leading to the Formation of Molecular Hydrogen in the Radiation Chemistry of Water

Reaction Mechanism Leading to the Formation of Molecular Hydrogen in the Radiation Chemistry of Water

Isotope Effects in the Radiation Chemistry of Water

Israel Journal of ChemistryVolume 2, Issue 6 p. 337-353 Article Isotope Effects in the Radiation Chemistry of Water Chava Lifshitz, Chava Lifshitz Department of Physical Chemistry, The Hebrew University of JerusalemSearch for more papers by this authorG. Stein, G. Stein Department of Physical Chemistry, The Hebrew University of JerusalemSearch for more papers by this author Chava Lifshitz, Chava Lifshitz Department of Physical Chemistry, The Hebrew University of JerusalemSearch for more papers by this authorG. Stein, G. Stein Department of Physical Chemistry, The Hebrew University of JerusalemSearch for more papers by this author First published: 1964 https://doi.org/10.1002/ijch.196400067Citations: 4AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume2, Issue61964Pages 337-353 RelatedInformation

Role of Oxygen in the Primary Formation of H and H2O− in the Radiation Chemistry of Water

Role of Oxygen in the Primary Formation of H and H2O− in the Radiation Chemistry of Water

The Radiation Chemistry of Water and Aqueous Solutions.

<b>The Radiation Chemistry of Water and Aqueous Solutions.</b>

Nature of the Precursors of Molecular Products in the Radiation Chemistry of Water

Research on radiation chemistry of water is reviewed with respect to the precursors of molecular hydrogen. Evidence is presented that the primary reducing species is the hydrated electron, H/sub 2/O-, and that molecular hydrogen is formed by two mechanisms, the major one being recombination of H/sub 2/O- and the minor one being recombination of H atoms formed by H/sup +/ reacting with H/sub 2/O-. (D.J.C.)

Books received

Books receivedPublished Online:28 Jan 2014https://doi.org/10.1259/0007-1285-35-411-210SectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail AboutAbstractBooks received are acknowledged under this heading and such notice may be regarded as an acknowledgment of the courtesy of the sender.Reviews will be published in the interest of our readers and as space permits.The Radiation Chemistry of Water and Aqueous Solutions. By A. O. Allen (D. Van Nostrand, London). Previous article Next article FiguresReferencesRelatedDetails Volume 35, Issue 411March 1962Pages: 149-220 © The British Institute of Radiology History Published onlineJanuary 28,2014 Metrics Download PDF

THE REACTIVITY OF HYDROGEN ATOMS IN THE LIQUID PHASE: THE LACK OF EFFECT OF LINEAR ENERGY TRANSFER IN THE RADIOLYSIS OF HYDROCARBONS

Discussion is given on the two characteristics of the hydrogen yields from pure cyclohexane and pure n-hexane. The characteristics are the apparent lack of contribution to the hydrogen yield by the reaction H + H not at the end of H/ for radiation of low LET, and the invariance of the yields with changing LET of the radiation. Various works are reviewed, and it is suggested that a possible explanation of these effects is that the initial decomposition occurs at larger distances from the position of energy deposition than is sometimes supposed in models for the radiation chemistry of water. This may be the result of an intermolecular dispersal of energy, or a diffusion of molecules without decomposition (or possibly the latter following the former).

RADIATION, ITS PRIMARY INTERACTIONS

A discussion is presented of some current thinking on the primary interactions of ionizing radiation with biological materials, including a brief discussion of ionization, excitation, the track phenomenon of charged particles, and the radiation chemistry of water. An attempt is made to correlate some of these phenomena with the variations in biological damage produced by various types of radiations incident on various biological systems and under varying conditions of oxygen tension.

Hydrogen Formation in the Radiation Chemistry of Water

The molecular hydrogen yields in concentrated aqueous sodium nitrate solutions by cobalt-60 gamma-ray irradiation have been observed and correlated with the molecular hydrogen yields observed in dilute solutions. The G(H2) plotted as the cube root of the NaNO3 activity exhibits a sharp break indicative of a change in the mechanism of formation. The predominant process, designated E1, is readily affected by a scavenging solute. A process of lessor magnitude, designated E2, is less susceptible to solute scavenging. The sharp break is interpreted as the cessation of the E1 process. The G(H2) observed in the NaNO3 solutions at 298° K is correlated with the G(H2) observed in ice at 77° K. Of paramount importance is the observation that the hydrogen formed by the E1 process may be eliminated by irradiation of aqueous nitrate solutions at 77° K. The G(D2) data observed in comparable D2O–NaNO3 solutions also exhibit the same mechanisms of formation. The isotope effect on the formation of D2 in D2O is in qualitative agreement with two initial distributions of the H atoms.