About the role of tunnelling in the reactions of positronium atom in liquids

Abstract

An expression for rate constant for diffusion controlled reaction of positronium atom /Ps/ with acceptor in condensed phase was obtained, accounting the tunnelling of Ps. The obtained equation is good also for description of the reactions of solvated electron with electroneutral molecules. Owing to the tunnelling transfer existence, the rate constant /k/ is the sum of two terms — the first of them is proportional to the coefficient of relative diffusion of reagents and the second one /characterizing the subbarrier reaction/ does not include the diffusion coefficient. The correlation of the calculated and experimentally obtained rate constants for Ps+O₂ reaction in liquids with different diffusion coefficients demonstrates good agreement between theoretical and experimental results. The possibility of electron tunnelling in liquid reaction of excited anthracene quenching with dissolved oxygen is also suggested.