Electron tunneling reactions between inorganic ion radicals and transition metal compounds

Electron tunneling reactions between inorganic ion radicals and transition metal compounds 

Radiolysis of vitreous aqueous solutions of H2S04 and NaOH is known to yield the anion radicals S04 and 0 which possess strong electron acceptor properties and are readily recorded by the characteristic EPR spectra [1, 2]. Reactions of electron transfer from FeS04 and AgN03 to S04, and from K4Fe(CN)6 to 0 at 77 and 4.2 K have been detected and investigated [3, 4]. 

The kinetics of S04 decay in the presence of both FeS04 and AgN03 is 

n(t)/n(t0) is the ratio of the current concentration, n(t), of the reagent present in the smaller amount (in this case S04 ) to its concentration at a certain fixed time moment, tof N is the concentration of the second reagent, and p = ndlj2) xvz vvtQ. In accordance with eqn. (1), the observed kinetics of S04 decay presents straight lines in the coordinates of Fig. 1. 

The fraction of the decomposed S04 anion radicals for a sample containing 0.05 M FeS04, y-irradiated at 77 K and then stored for 24 h at 4.2 K, accounts for 31% of their total amount 20 min after the irradiation while for the reference sample irradiated in the same conditions but stored at 77 K, this fraction is 35%. Thus, the decay of S04 , at least in the reaction with FeS04 at T 77 K, proceeds virtually with zero activation energy. 

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