Gideon Czapski

The use of deciles of the citation impact to evaluate different fields of research in Israel

One often uses the average citation impact factor in order to perform international comparisons between the levels of scientific performance within given disciplines. In averaging over all (or all cited) papers one may gives undue weight to papers with few citations while, in fact, the standing of a country within a given field would be better assessed by looking only at the “successful” papers in that discipline. The present papers suggests that one should do so by averaging citations only over the ten (or twenty) percent of the most cited papers in a discipline and use these in order to establish a ranking between countries. The case of Israel is used as an illustration of this approach.

On the existence of dielectrons in aqueous solutions

Abstract Alkaline aqueous solutions under high H 2 pressures when pulse radiolysed should favor the formation of dielectrons through the reaction e aq − + e aq − → (e 2 −2 )aq → H 2 + 2OH − . In our pulse radiolysis investigation of such solutions, no U.V. absorption, which can be attributed to the decay of e aq − , remains after the decay of e aq − . We conclude that either dielectrons scarcely absorb any light in the region where e aq − absorbs or else the dielectron is quite short-lived as compared to the lifetime of e aq − under these conditions.

The role of the reaction of eaq - with FeIII in the radiation chemistry of acid aqueous solutions

Abstract The reaction Eaq-+Fe2 Fe2+ was investigated by competition with the reaction Eaq-+H+ H. In acid solutions of alcohol, G(H2) was reduced very efficiently by FeIII. K 1 k 2 was determineed in HClO4 and H2SO4 and it was found to depend on the form of FeIII ion in solution. At pH 1·8, k 1 k 2 ≈2 in both HClO4 and H2SO4. Inclusion of this reaction in the mechanism of oxidation of Fe2+ in acid solutions (which has been generally neglected) confirms, as suggested by Schwarz(2), that Geaq - seems to be almost pH independent. It also removes the necessity of assuming the existence of H2O2+ which was proposed(4) (Pucheault et. al., Int. J. Radiat. Phys. Chem. 1969. 1, 209) in order to interpret the variation of G(FeIII) in acid air-saturated FeIII/Fe2+ solutions.