Study by EPR of unsteady species produced at low temperature by γ irradiation of single-crystals of malonic acid

This research thesis reports the study of the radiolysis of the malonic acid during which two different radicals are formed. The objective was then to know the sequence of reactions which occur to pass from primary species (positive ion, negative ion) to radicals finally observed by electronic paramagnetic resonance (EPR) at room temperature. After some theoretical recalls on EPR and on the theoretical calculation of spin density, the author presents experimental conditions (elaboration of per-deuterated malonic acid, and of single crystals, radiolysis of single-crystals and EPR-based measurement). Results are then presented in terms of spectrum analysis, radical structure, radical reaction mechanisms, and radical pairs.