An experiment with manifold purposes: the chemical reactivity of crystal defects upon crystal dissolution

Abstract

A few years ago we carried out some experiments concerning the fate of F centers in alkali halides upon crystal dissolution. It has been ascertained that these centers give rise to hydrated electrons, e~q, which were counted by using the method of competition kinetics (1). At the same time, it was implicitly proven that the ejq are generated in amounts suitable for investigating their chemical reactivity (2). In addition, the method devised for counting e7q, and therefore the F centers, has been applied to determination of the oscillator strength of the F centers in several alkali halides (3,4).Since the techniques used in these experiments are not too complicated and the instrumentation required is available in all radiochemical laboratories, we have tried to adapt these measurements for use as a classroom experiment in either a radiochemistry course or a solid state physical chemistry course. This experiment will introduce:1) crystal defects and their reactivity upon crystal dissolution; 2) the hydrated electron and its reactivity; 3) an application of the radiochemical method of analysis; 4) the technique of competitive kinetics (even though it is applied to a rather particular case).

A reappraisal of the role of the low potential c-type cytochrome (cytochrome c-552) in NADH-dependent nitrite reduction and its relationship with a co-purified NADH oxidase in Escherichia coli K-12

“…coli [12], the NADH-dependent nitrite reductase activity was found to be responsible for the physiological function [5]. coli [12], the NADH-dependent nitrite reductase activity was found to be responsible for the physiological function [5].…”