Field-cycled dynamic nuclear polarization (FC-DNP) of 14N and 15N nitroxide free radicals at low magnetic field

C. Polyon, David John Lurie, W. Youngdee, C. Thomas, I. Thomas

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3 Citations (Scopus)

Abstract

Theoretical Overhauser-detected EPR spectra of N-14 and N-15 nitroxide systems in low magnetic field by field-cycled dynamic nuclear polarization ( FC-DNP) were described by a combination of DNP theory and a model of FC-DNP. Spectra were simulated at magnetic fields between 0 and 8 mT. The simulations were able to predict both the EPR peak positions and their amplitudes, corresponding to those from FC-DNP experiments with 14N and 15N TEMPOL solutions. EPR irradiation was in the 45-133MHz range while NMR signal detection occurred at a field of 59 mT. At this frequency range, four p transitions of a 14N system and three p transitions of a 15N system were observed. The simulation programmes were also used to predict the spectral amplitudes of the FC-DNP with EPR irradiation power in the 1-15W range. Theoretical FC-DNP systems were in good agreement with experimental results; however, at low magnetic fields the inhomogeneity of our magnet system resulted in the EPR peaks being left-shifted and somewhat broader than those from the theoretical prediction.

Original languageEnglish
Pages (from-to)5527-5532
Number of pages6
JournalJournal of Physics D: Applied Physics
Volume40
Issue number18
DOIs
Publication statusPublished - 21 Sep 2007

Keywords

  • optimization
  • transitions
  • pedri
  • sigma
  • spin
  • PI

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