Electron spin resonance of Cu2+ impurities in L-arginine phosphate monohydrate single crystals

Abstract Using electron paramagnetic resonance spectroscopy we studied single crystals of l -arginine phosphate monohydrate doped with copper. The angular dependence of the spectrum in three orthogonal planes shows that the Cu 2+ ions occupy two symmetry related sites in the structure. The Zeeman and hyperfine coupling tensors were determined. The principal values are: g 1 =2.053, g 2 =2.054, g 3 =2.251, A 1 ≈0, A 2 =24×10 −4 cm −1 and A 3 =177×10 −4 cm −1 . Superhyperfine interactions with 14 N ligands, well resolved for certain orientations of the magnetic field, suggest that Cu impurities have three N ligands. In terms of the molecular structure and based in similar systems, our findings are discussed and suggestions are made.