ИСТИНА

Emission of the energized Auger-electrons just after formation of the Mössbauer nucleus 57 Fe leads not only to formation of the multi-charged ion 57 Fe n+ , but to formation of a cloud of many (200- 300) ion-electron pairs (H2O + , e - ) around this 57 Fe ion. Such a cloud is called as the Auger-blob [1, 2]. Its radius is about ~100 Å. Formation of the blob takes about 10 -13 s. Further fast radiation-chemical reactions in the Auger-blob (ion-electron recombination, electron localization and scavenging) determine experimentally observable ratio of the yield of final chemically stable ions Fe 3+ and Fe 2+ . This ratio is important for adequate interpretation of the emission Mössbauer spectra. Reduction of the Fe 3+ ion to the Fe 2+ state occurs because of interaction with one of the blob quasifree electrons. Generally speaking, intrablob reactions proceed together without diffusion of the blob species, but this expansion of the blob is suppressed because of low mobility of the positively charged ions in the disordered frozen medium. Out-diffusion of the secondary electrons is also suppressed due to electrostatic attraction to immobile positive ions (it is so called ambipolar diffusion). Diffusionrecombination stage of the intrablob reactions is terminated by electron localization on structural traps (it takes about 10 -7 s). Further behavior of the trapped electrons is governed by their tunneling to positive ions or to the dissolved electron scavengers. This stage elapses much longer (up to hours) and may be observed by EPR spectroscopy and pulse radiolysis method. By means of the emission Mössbauer spectroscopy we have studied experimentally reaction ability of NO3
cations towards quasifree track electrons in frozen aqueous solutions of acids and salts. It was shown that NO3
scavenges track electron more efficiently (but only by a factor of 3) then H3O + , ClO4
, HSO4
ions towards same electrons. This fact is in a drastic contradiction with radiation chemical literature data, which indicate that these reaction abilities deviate almost by two orders of magnitude. Origin of this contradiction is related with the different mechanism of electron trapping by NO3
and H3O + ions. In case of H3O + , electron trapping leads to formation of H3O
state, which decays into H-atom and H2O, but decay process requires some free volume close to H3O
. This requirement strongly suppresses e
trapping ability of H3O + ions. Our estimations are related to frozen aqueous solutions, but they can be easily applied to media of another chemical composition