To the theory of nonstationary diffusion-controlled tunnelling chemical reactions

The kinetics of scavenging of short-lived light chemically active particles (excess electron, positronium) governed by their diffusion and tunnelling is calculated. In case of slow diffusion motion, the decay kinetics of the particle (probe) is calculated by means of perturbation theory over the diffusion operator. In the opposite case, the scattering length theory is used. Both approaches are well matched in the intermediate region. This model presents a basis for interpretation of the lifetime e+-e- annihilation spectra and improves former approaches to the decay of the excess trapped electrons in frozen matrices