E. Sagstuen1, E. O. Hole1, S. R. Haugedal1, A. Lund2, O. I. Eid2,3, R. Erickson2
1 Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo, Norway,
2 Department of Physics and Measurement Techniques, Linköping University, S-581 83 Linköping, Sweden,
3 permanent address: Department of Physics, Faculty of Science, University of Khartoum, P.O. Box 321, Khartoum, Sudan
The microwave power dependency of satellite lines caused by three distant protons, (3H) in X-band EPR spectra of CO2-... (3H) in NaHC2O4· H2O, and the SAR, CH3CHCOO-... (3H), in L-alanine was analysed by line shape simulation. The distant protons are hydrogen-bonded to the radical in the first case and the methyl protons of a neighbouring alanine molecule in the second case. The radicals were produced by X-irradiation. A simulation programme was developed which includes a phenomenological adaptation of continuous saturation theory. Refined g- and hyperfine data including the interaction with the three neighbouring protons of the SAR were obtained by ENDOR and EPR, while previously determined parameters were used in the EPR simulation of the CO2- ... (3H). Good agreement was obtained between experimental and simulated single crystal spectra over a microwave power region from none to strong saturation. Simulation of the SAR powder spectrum deviated more from the experimental at saturation, probably because of the presence of other radicals. The findings are discussed in the context of EPR dosimetry.