Theory of Radiation Chemistry. IV. Chemical Reactions in the General Track Composed of <i>N</i> Particles

Monchick, L.; Magee, John L.; Samuel, Aryeh H.

doi:10.1063/1.1743438

Cited by 84 publications

(22 citation statements)

References 12 publications

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“…These species are assumed to be consumed exclusively in the spurs and, in the absence of scaven gers, to participate only in the formation of H 2 and H 2 O 2 . Similar to the theory proposed in [3,11], the species Se1, Se2, SOH1, and SOH2 in the absence of a scavenger combine with each other in the spurs via the following reactions:…”

Section: Calculation Proceduresmentioning

confidence: 99%

Simulation of the radiation-chemical yields of hydrogen and hydrogen peroxide in concentrated solutions

2014

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A method based on the use of descriptive kinetics of elementary reactions has been proposed for calculating the yields of H 2 and H 2 O 2 in concentrated solutions. The influence of scavengers on the primary yields was taken into account by introducing into the scheme of radiation chemical transformations addi tional reactions with the radical ion products of water radiolysis that compete with the H 2 and H 2 O 2 forma tion reactions in "spurs." The proposed calculation scheme allows the change in the initial yields in the pres ence of scavengers to be directly included in the general scheme of radiation chemical transformations. The scheme satisfactorily describes the observed yields in concentrated nitrate and nitrite solutions, which form the base medium of liquid radioactive waste to be disposed in geological repositories.

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Section: Calculation Proceduresmentioning

confidence: 99%

Simulation of the radiation-chemical yields of hydrogen and hydrogen peroxide in concentrated solutions

2014

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“…To avoid this impossible task, we use the superposition approximation. 13,18,24,26 For instance, we have…”

Section: ͑221͒mentioning

confidence: 99%

Diffusion-influenced radical recombination in the presence of a scavenger

Kim

Jung

Jeon

et al. 1996

The Journal of Chemical Physics

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The recombination reaction of radicals photolytically produced in solution proceeds via two distinguishable kinetic phases. At short times recombination between geminate radicals predominates, while at long times recombination between nongeminate radicals that have diffused away from their geminate counterparts to the bulk solution takes place. In most previous theories dealing with the effect of added scavenger molecules on the radical recombination reaction, only the geminate recombination phase has been considered. However, if the concentration of radical pairs generated is high, the interplay of bulk recombination in the dynamics needs to be considered. In the present paper, we formulate a theory that deals with the scavenging effect in both the geminate and bulk recombination phases within a unified framework. We show that the scavenger concentration C S and the scavenging rate coefficient k S have independent effects on the reaction, in general. In contrast, conventional theories involve these two quantities only as a product k S C S , usually in the form of a Laplace transformation variable.

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“…Equation (3.6), is generally solved numerically (eg, Kuppermann, 1975;Burns et al, 1984) and then integrated over space to give the expected number of surviving particle as a function of time. Alternatively, the approximation of prescribed diffusion is used (Jaffe, 1913;Monchick et al, 1957). This approximation assumes that the concentration is always proportional to a spherical Gaussian density with variance equal to 0"6 + 2Dt, ie, the effect of reaction is assumed merely to change the normalisation constant.…”

Section: Continuum Approximationsmentioning

confidence: 99%

Statistical Models of Chemical Kinetics in Liquids

Clifford

Green

Pilling

1987

Journal of the Royal Statistical Society Series B: Statistical Methodology

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Statistical methods are used increasingly in theoretical chemistry. Applications range from the use of stochastic relaxation techniques in determining minimum energy molecular configurations to dynamical Monte Carlo simulations of molecular motion in liquids. This paper focuses on diffusion-controlled reactions in radiation chemistry. Here the interest is in describing the evolution of isolated clusters, containing a few chemically active particles, resulting from the passage of ionising radiation through a liquid. The subsequent chemistry is determined by the rate at which these particles can encounter each other, pairwise, in the course of their random motion. Classically the trajectories of the particles are described as sample paths of a continuous stochastic process, which in many cases can be assumed to be a diffusion. We have devised an approximate theory based on the approximation that pair distances evolve independently. The effect of this geometric distortion has been studied for small systems by simulation. The extension of this work to a wider class of realistic chemical processes poses many problems. Analytical progress is difficult and methods of simulating large spatial systems are not well developed. Problems which remain to be solved relate to the random geometry of the cluster as its constituent particles diffuse, the development of good approximations to first passage time distributions for diffusions with inhomogeneous drift and methods for the analysis of random motion in a liquid on the basis of detailed non-Markovian models of molecular movement.

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Theory of Radiation Chemistry. IV. Chemical Reactions in the General Track Composed of N Particles

Cited by 84 publications

References 12 publications

Simulation of the radiation-chemical yields of hydrogen and hydrogen peroxide in concentrated solutions

Simulation of the radiation-chemical yields of hydrogen and hydrogen peroxide in concentrated solutions

Diffusion-influenced radical recombination in the presence of a scavenger

Statistical Models of Chemical Kinetics in Liquids

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