Using the EPR-and IR-spectroscopy methods, we studied the conditions of formation of stable ion-radicals in the structure of calcium sulfite and determined the limits of their stability. We detected and identified the ionradicals SO 2 − with g(iso) = 2.0055 in the initial substances, two types of thermally induced SO 2 − (with g 1 = 2.0093, g 2 = 2.0045, and g 3 = 2.0020, and g 1 = 2.0104, g 2 = 2.0049, and g 3 = 2.0018) when the substance was heated, and three types of mechanically induced SO 3 − (with g M = 2.0036 and g N = 2.0022, with g(iso) = 2.0033 and ∆H = 0.1 mT and with g(iso) = 2.0031 and ∆H = 0.33 mT) when the substance was ground up.Keywords: EPR and IR spectroscopy, EPR dosimetry, sulfite and sulfate anions, SO 2 − and SO 3 − ion-radicals.Introduction. One possible method of reconstruction of absorbed doses of ionizing radiations applied in spinresonance dosimetry and in the region of EPR dating of geological and archeological materials is the cumulative-dose method [1]. It is based on determination of the concentration of accumulated radiatively induced paramagnetic particles and involves an initial mechanical or thermal processing of the object under study and subsequent additional irradiation of this object. In the course of preliminary preparation, mechanically and thermally induced paramagnetic particles can form in the substance that have g factors close to the values of the g factors (or coinciding with them) for radiatively induced paramagnetic particles. As a result, additional, often neglected, errors are brought into the unknown value of the reconstructed dose and make its determination difficult. In view of this, there is a pressing need to investigate the nature of nonradiative paramagnetic particles, the mechanisms of their formation, and the conditions of stabilization in a substance.Along with other materials, carbonates of natural origin are used to reconstruct absorbed doses. The characteristic feature of these carbonates is the presence of sulfite-anions [2, 3]. Moreover, it is known that such a compound as barium sulfite in the absence of irradiation is capable of stabilizing ion-radicals in its structure [4,5]. Starting from this, it is the aim of the present work to elucidate the nature, the conditions of formation, and the stability of paramagnetic particles in the structure of nonirradiated calcium sulfite (CaSO 3 ), which is necessary for further evaluation of their contribution to the unknown value of the absorbed dose in natural carbonates.Experimental Technique. Calcium sulfite was synthesized at 20 o C by adding a solution of sodium sulfite to a solution of calcium chloride with subsequent filtering of the sediment and drying of it in air without heating. The purity of the salt obtained was controlled by x-ray phase analysis and IR spectroscopy. We used a DRON-3 x-ray diffractometer and a Prote ′ ge ′ 760 IR Fourier-spectrophotometer (Nicolet, USA). Specimens were tableted together with KBr.The calcium sulfite obtained was divided into two parts, one of which was ground u...
