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F. A. M, DE HAAN
with H,O*. The oxidation of Tlf to T1+Zby H,O* may account for the increased apparent yield of OH observed by Hayon.’ The formation of eaq- by the reaction of iodide with H20* may also explain the increased yield of “niolecular hydrogen” in concentrated iodide solutions.14r18 The existence of oxidizing species other than OH radicals in neutral irradiated solution has been reported recently by different investigators29s30and their identity has not been finally established. These species manifest themselves only in rather concentrated solutions, in analogy to the experinients described in the present study. It is suggested here that either HzO+ or H20* or most probably both are liable for these findings. Both species are undoubtedly primary products of the act of radiation on water.31 The only question is whether these will
not dissociate or undergo deactivation before having a, chance to interact with solutes. Our postulation is that mater molecules which are both in thc inner and outer hydration shells of a given ion and which undergo a radiolytic ionization or excitation are liable to interact with their central ion rather than dissociate to Hf OH or H OH, respectively, or alternatively undergo neutralization or de-excitation. The rate of interaction of H 2 0 +or H20* formed in the hydration shell of a given solute with thcir central atom or molecule niay be of the order of electronic transition within a molecule, ie.,
Introduction The predoniinantly negative charge on l,,ost soil colloids leads to a decrease of the aniorl concentration in the close vicinity of the colloidal particles as compared with the concentration in the equilibrium solution. Thc .Joirrnal
OJ
P h p i c a l Chcmistrlj
This deficit of anions has been termed negative adsorption or anion exclusion. An expression for the negative adsorption, based on theoretical model calculations, was derived by Schofieldl and I
