Radiation chemical diffusion kinetic calculations with prescribed and non-prescribed diffusion—I

Burns, W. G.; Sims, Howard E.; Goodall, J.A.B.

doi:10.1016/0146-5724(84)90105-5

Cited by 62 publications

(39 citation statements)

References 17 publications

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“…We simulate evolution of the radiolytic species during the spur expansion in N 2 O saturated aqueous solution of 0.1 M HCl using the extended diffusionkinetic approach, 20 successfully adopted to reproduce the pH effect on spur chemistry in irradiated aqueous solutions. 21 The computations have been based on the numerical algorithm, developed by Burns et al, 22 which divides the reaction space into a number of concentric zones and treats reactions in each zone and simultaneous mass ow between adjoining zones according to the Fick's law of diffusion. The reactants were placed into each zone according to the initial Gaussian distributions.…”

Section: Diffusion-kinetic Modelling Of Spur Chemistrymentioning

confidence: 99%

Reaction of the hydrogen atom with nitrous oxide in aqueous solution – pulse radiolysis and theoretical study

2017

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Section: Diffusion-kinetic Modelling Of Spur Chemistrymentioning

confidence: 99%

Reaction of the hydrogen atom with nitrous oxide in aqueous solution – pulse radiolysis and theoretical study

2017

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“…To deal with non-uniform distribution of the reactants, the model adopted the numerical procedure proposed by Burns et al [8]. According to this procedure, the reaction space is divided into a number of concentric zones where the reactants are distributed according to the Gaussian function.…”

Section: Details Of the Calculationsmentioning

confidence: 99%

Modelling spur chemistry for alkaline and acidic water at high temperatures

Swiatla-Wojcik

2009

Res Chem Intermed

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The effect of pH and associated ionic strength on the primary yields in the radiolysis of pressurised water has been assessed by diffusion-kinetic calculations for temperatures in the range 100-300°C. Account has been taken for ionic strength I up to 0.1 mol kg -1 , assuming that the counter ions of H ? in acid solutions and of OH -in base solutions have unit charge. In acid solutions, the H ? ions react with eaq . The decrease in G(eaq ) and the increase in G(H) with decreasing pH becomes substantial for [H ? ] C 1 9 10 -4 m, but the primary yields of oxidising species are almost constant. In alkaline solutions, the OH -anions affect the spur chemistry of radiation-generated protons and hydroxyl radicals for [OH -] C 1 9 10 -4 m. The scavenging of H atoms and hydrogen peroxide becomes significant for [OH -] C 1 9 10 -2 m. The total yields G(OH) ? G(O -) and G(H 2 O 2 ) ? G(HO 2 -) are independent of base concentration below 0.01 m. In more alkaline solutions, G(OH) ? G(O -) increases, whereas G(H 2 O 2 ) ? G(HO 2 -) decreases with increasing [OH -]. Calculations showed the substantial yield of the reaction O -? eaq in 0.1 m base solution. Spur chemistry in alkaline hydrogenated water is not affected by the presence of H 2 if less than 0.001 m of hydrogen is added.

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“…The rate function k~A(t) is proportional to the hazard function, A(t) in (3.2) when the probability density lis uniform over a large volume. 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).…”

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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Radiation chemical diffusion kinetic calculations with prescribed and non-prescribed diffusion—I

Cited by 62 publications

References 17 publications

Reaction of the hydrogen atom with nitrous oxide in aqueous solution – pulse radiolysis and theoretical study

Reaction of the hydrogen atom with nitrous oxide in aqueous solution – pulse radiolysis and theoretical study

Modelling spur chemistry for alkaline and acidic water at high temperatures

Statistical Models of Chemical Kinetics in Liquids

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