ESR study of γ-Irradiated N α -Acetyl-L histidine monohydrate

Abstract

The electron spin resonance of γ-irradiated single crystals of N α -Acetyl-L Histidine Monohydrate, C 8 H 11 N 3 O 3 .H 2 O 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 (σ radical), R 2 -NCH (π radical) and C 2 H 2 CH 2 . 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 R-N H and g = 2.0042, a H = 90 G, a N = 10 G for R 2 -NC H and g = 2.0047, a H = 30 G, a Hβ = 10 G for C 2 H 2 CH 2 .