EPR of manganese-containing plasticine: Spectral simulation and use as an internal standard for comparison of the signal intensities of various free-radical EPR spectra

• Published in: Applied magnetic resonance 2003-03, Vol.24 (1), p.113-125
• Main Authors: Rahimi-Moghaddam, P., Upadrashta, Y., Nilges, M. J., Weil, J. A.
• Format: Article
• Language: English
• Subjects: Adducts; Electron paramagnetic resonance; Free radicals; Hydroxyl radicals; Manganese; Plasticine; Quadrupoles; Room temperature; Spectra
• ISSN: 0937-9347; 1613-7507
• DOI: 10.1007/BF03166683

Electron paramagnetic resonance spectra of manganese-containing plasticine putty have been obtained both at 9.4 and 94.2 GHz (room temperature). It has been possible to analyze both, quantitatively by computer-based simulation and exact diagonalization of a general spin-Hamiltonian, by use of an appropriate powder technique. A fine fit was obtained for both frequencies with an isotropicg-2.00117, uniaxial55Mn hyperfine valuesA∥/gcβc = −93.5 G (where ‖ implies direction (ℤ) andA⊥/gcβc = −94.3 G, a nuclear quadrupole effectPz(55Mn)=0, and a uniaxial electronic quadrupole matrix (D/gcβc = 3DZ/2gcβc = −82.8 G). The electronic octupole energy was taken into account via the single parameterB40/gcβc = −0.024 G. The plasticine has been demonstrated to afford a fine intensity and magnetic-field standard, say, for use with free radicals such as spin-trap adducts. Examples provided are 2,2-diphenyl-l-picrylhydrazyl, and hydroxyl radical generated by the Fenton reaction and spin-trapped with 5,5-dimethyl-1-pyroline-N-oxide.