Formation of the NO2 radical during radiolysis of sodium nitrate

There is disagreement concerning the formation of NO2 during irradiation of potassium and sodium nitrates at 77 K. For example, in [1], it was determined that the NO2 radical is formed at 77 K only in the presence of a nitrite impurity ion. At the same time, according to the data of [2], a NO2 radical was formed at this temperature in a pure nitrate. In the present paper, the authors investigated the formation of the NO2 radical in irradiated single crystals of nominally pure sodium nitrate at 77 K in a wide range of absorbed doses