Pulse radiolysis with Čerenkov detection vs conventional approach

Abstract

Čerenkov Light Selfabsorption Method (ČLSM) consists of the recording of light emitted by a sample in the beam of electrons. If there is no formation of intermediates absorbing light at the chosen wavelength, the shape of the intensity vs time curve is exactly the same as the current vs time profile of the electron pulse. Attenuation of Čerenkov light in the function of time means that a product is formed, and the resulting absorption at different wavelengths is used for the construction of the spectrum at different periods during the pulse. In the case of a transparent sample, liquid or solid, the spectrum obtained by the ČLSM may be compared with the spectrum obtained by conventional pulse radiolysis, i.e. from the absorption of external analytical light. Such experiments show perfect identity of spectra. The method has little application to liquids except cases in which photochemical effects due to intensive external analytical light have to be avoided. Full advantages of the Čerenkov method are shown in the case of pulse radiolysis of semitransparent and opaque solids. Therefore the method may be recommended in cases where application of conventional pulse radiolysis method is not possible. Still unexplored possibilities, especially concerning chiral solids are hidden in the method, because the Čerenkov light is circularly polarized.