The applicability of the diffusion-drift model of radiolysis of non-polar organic fluids containing additives of charged particle acceptors

Abstract

The conditions determining the limits of applicability of the diffusion-drift model (DDM) of radiolysis of non-polar organic fluids containing additives of acceptors of charged particles have been obtained. The validity of the DDM for saturated hydrocarbons is associated with the localization of the electrons which move in the medium by thermally activated jumps from one localized state to another. It is shown that the use of the DDM in radiation-chemical kinetics is justified if the lenght of localization l (or the mean length of the free path Λ) of the electrons is small as compared with the characteristic dimension of the problem. For describing the death of ion pairs such a characteristic dimension is the mean initial distance between their components and for calculating the rate constants of the reactions of recombination and capture of the charges by an acceptor the radius of the absorbing sphere R. The corrections arising from calculation of these constants for the systems where l_L (or Λ) is greater than or comparable with R are evaluated.