Advertisement

Applied Magnetic Resonance

, Volume 34, Issue 3–4, pp 355–378 | Cite as

Multidimensional Low-Power Pulse EPR under DNP Conditions

  • J. Granwehr
  • W. Köckenberger
Article

Abstract.

Several different processes and potentially even multiple different mechanisms are involved in the dynamic nuclear polarization (DNP) of bulk nuclei in a solid matrix doped with paramagnetic centers. This has to date prevented the quantification of DNP on the basis of a mechanistic understanding for paramagnetic agents with an electron paramagnetic resonance (EPR) spectrum broader than the Larmor frequency of the nuclei that are polarized. To compare theoretical models with experiments, it is necessary to gather experimental data to quantify all the involved processes. On the basis of an EPR setup using the same unstabilized microwave source as is used for DNP, we present multidimensional correlation EPR experiments to study the electron spin dynamics under DNP conditions. Low-power pulse EPR methods are used to measure the transient saturation and saturation–recovery on a timescale of tens to hundreds of milliseconds. Furthermore, the absence of a microwave resonator or cavity enables us to perform pump–probe experiments with switching of the microwave frequency. The correlation patterns obtained with these electron–electron double-resonance experiments can be used to analyze spectral diffusion in the EPR spectrum of the investigated radicals. In addition to studying the dynamical properties of the electron spins, it is shown for TEMPO in a glassy matrix that these experiments can be used to directly measure DNP of strongly hyperfine-coupled nuclei, in this case the nitroxyl-14N.

Keywords

Electron Paramagnetic Resonance Electron Paramagnetic Resonance Spectrum Pump Pulse Dynamic Nuclear Polarization Electron Paramagnetic Resonance Line 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Abragam, A., Goldman, M.: Rep. Prog. Phys. 41, 395–467 (1978)CrossRefADSGoogle Scholar
  2. Rosay, M., Weis, V., Kreischer, K., Temkin, R., Griffin, R.G.: J. Am. Chem. Soc. 124, 3214–3215 (2002)CrossRefGoogle Scholar
  3. Ardenkjaer-Larsen, J.H., Fridlund, B., Gram, A., Hansson, G., Hansson, L., Lerche, M.H., Servin, R., Thaning, M., Golman, K.: Proc. Natl. Acad. Sci. USA 100, 10158–10163 (2003)CrossRefADSGoogle Scholar
  4. Wollan, D.S.: Phys. Rev. B 13, 3671–3685 (1976)CrossRefADSGoogle Scholar
  5. Abragam, A., Proctor, W.G.: C. R. Acad. Sci. Paris 246, 2253–2256 (1958)Google Scholar
  6. Bloembergen, N., Shapiro, S., Pershan, P.S., Artman, J.O.: Phys. Rev. 114, 445–459 (1959)CrossRefADSGoogle Scholar
  7. Farrar, C.T., Hall, D.A., Gerfen, G.J., Inati, S.J., Griffin, R.G.: J. Chem. Phys. 114, 4922–4933 (2001)CrossRefADSGoogle Scholar
  8. Hyde, J.S., Chien, J.C.W., Freed, J.H.: J. Chem. Phys. 48, 4211–4226 (1968)CrossRefADSGoogle Scholar
  9. Rengan, S.K., Rhagat, V.R., Sastry, V.S.S., Venkataraman, B.: J. Magn. Reson. 33, 227–240 (1979)Google Scholar
  10. Saalmueller, J.W., Long, H.W., Maresch, G.G., Spiess, H.W.: J. Magn. Reson. A 117, 193–208 (1995)CrossRefGoogle Scholar
  11. Mango, S., Runólfsson, Ö., Borghini, M.: Nucl. Instrum. Methods 72, 45–50 (1969)CrossRefADSGoogle Scholar
  12. Becerra, L.R., Gerfen, G.J., Bellew, B.F., Bryant, J.A., Hall, D.A., Inati, S.J., Weber, R.T., Un, S., Prisner, T.F., McDermott, A.E., Fishbein, K.W., Kreischer, K.E., Temkin, R.J., Singel, D.J., Griffin, R.G.: J. Magn. Reson. A 117, 28–40 (1995)CrossRefGoogle Scholar
  13. Granwehr, J., Leggett, J., Köckenberger, W.: J. Magn. Reson. 187, 266–276 (2007)CrossRefADSGoogle Scholar
  14. Whitfield, G., Redfield, A.G.: Phys. Rev. 106, 918–920 (1957)CrossRefADSGoogle Scholar
  15. Bloembergen, N., Damon, R.W.: Phys. Rev. 85, 699 (1952)CrossRefADSGoogle Scholar
  16. Hervé, J., Pescia, J.: C. R. Acad. Sci. Paris 251, 665–667 (1960)Google Scholar
  17. Du, J.-L., Eaton, G.R., Eaton, S.S.: J. Magn. Reson. A 115, 213–221 (1995)CrossRefGoogle Scholar
  18. Shikata, H.: Bull. Chem. Soc. Jpn. 50, 3084–3089 (1977)CrossRefGoogle Scholar
  19. Epel, B., Pöppl, A., Manikandan, P., Vega, S., Goldfarb, D.: J. Magn. Reson. 148, 388–397 (2001)CrossRefADSGoogle Scholar
  20. Harbridge, J.R., Eaton, S.S., Eaton, G.R.: J. Magn. Reson. 159, 195–206 (2002)CrossRefADSGoogle Scholar
  21. Freed, J.H.: J. Phys. Chem. 78, 1155–1167 (1974)CrossRefGoogle Scholar
  22. Hyde, J.S., Pasenkiewicz-Gierula, M., Jesmanowicz, A., Antholine, W.E.: Appl. Magn. Reson. 1, 483–496 (1990)CrossRefGoogle Scholar
  23. Press, W.H., Teukolsky, S.A., Vetterling, W.T., Flannery, B.P.: Numerical Recipes in C, 2nd edn. Cambridge University Press, Cambridge (1992)zbMATHGoogle Scholar
  24. Portis, A.M.: Phys. Rev. 91, 1071–1078 (1953)CrossRefADSGoogle Scholar
  25. Dubinskii, A.A., Maresch, G.G., Spiess, H.W.: J. Chem. Phys. 100, 2437–2448 (1994)CrossRefADSGoogle Scholar
  26. Vugmeister, B.E.: Phys. Status Solidi B 76, 161–170 (1976)CrossRefGoogle Scholar
  27. Abragam, A.: Principles of Nuclear Magnetism. Oxford University Press, Oxford (1961)Google Scholar
  28. Hyde, J.S., Froncisz, W., Mottley, C.: Chem. Phys. Lett. 110, 621–625 (1984)CrossRefADSGoogle Scholar
  29. Eichel, R.A., Granwehr, J., Schweiger, A.: J. Magn. Reson. 162, 380–384 (2003)CrossRefADSGoogle Scholar
  30. Flokstra, J., Gerritsma, G.J., van der Marel, L.C.: Physica B 94, 53–59 (1978)CrossRefGoogle Scholar
  31. Atsarkin, V.A.: Sov. Phys. Usp. 21, 725–745 (1978)CrossRefADSGoogle Scholar
  32. Genack, A.Z., Redfield, A.G.: Phys. Rev. B 12, 78–87 (1975)CrossRefADSGoogle Scholar
  33. Schweiger, A., Ernst, R.R.: J. Magn. Reson. 77, 512–523 (1988)Google Scholar
  34. Granwehr, J., Schweiger, A.: Appl. Magn. Reson. 20, 137–150 (2001)CrossRefGoogle Scholar
  35. Stoll, S., Schweiger, A.: J. Magn. Reson. 177, 390–403 (2005)CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • J. Granwehr
    • 1
  • W. Köckenberger
    • 1
  1. 1.Sir Peter Mansfield Magnetic Resonance Center, School of Physics and AstronomyUniversity of NottinghamNottinghamUK

Personalised recommendations