Time-resolving ESR spectroscopy - methodical and instrumental fundamentals of ESR pulse radiolysis and ESR laser photolysis

With the development of time-resolving ESR spectroscopy the experimental possibilities to study the microdynamic and kinetic properties of free radicals in the liquid phase have been essentially improved. Starting from the physical and chemical requirements the basic principles of analysis of ESR time profiles are presented. The main components of the ESR pulse radiolysis equipment are described and their technical parameters are discussed. Besides the broad band signal registration the problems of data acquisition and computer-controlled signal analysis are considered particularly. The two cavities of H102- and E110-type are compared in connection with problems of optimal sensitivity. By two experimental examples it is shown that at a time resolution of 0.5μs a sensitivity of c/sub min/ = 10-6 mol dm-3 for simple radical spectra can be achieved. (author)