RADIATION EFFECTS AND DEFECTS IN SOLIDS, cilt.158, sa.8, ss.599-602, 2003 (SCI-Expanded)
The electron spin resonance of gamma-irradiated single crystals of N-alpha -Acetyl-L Histidine Monohydrate, C-8 H11N3O3 . H2O has been observed and analysed for different orientations of the crystal in the magnetic field. The crystals have been investigated between 100 and 400 K. The spectra were found to be temperature independent and the radiation damage centres are attributed to R-1 NH (sigma radical), R-2 NCH (pi radical) and C2H2CH2 . The g and hyperfine coupling constants were found to be almost isotropic with an average g = 2.0045, a(N) = 10 G, a(H) = 130 G for RNH and g = 2.0042, a(H) = 90 G, a(N) = 10 G for R-2 NC H and g = 2.0047, a(Halpha) = 30 G, a(Hbeta) = 10 G for C-2 H2CH2 .