Numerical investigation of tunnelling contributions to electron scavenging reactions in liquids at short times

Fick's second diffusion equation, with an added exponential sink term, is integrated numerically to simulate the decay of electrons at short times in the presence of scavengers. The time dependence of the scavenger concentration profile, the scavenging rate constant, and the electron concentration are illustrated graphically. Using the experimental results of Buxton et al. and Jonah et al. It is shown that the Smoluchowski equation is valid within their experimental time ranges provided the cage encounter distance is replaced by R eff , where R eff can be evaluated explicitly in terms of reaction parameters. It is also shown that tunnelling from relaxed traps may make a significant contribution to ultra-short time electron scavenging.