Thursday, June 21, 2012

Dynamic Nuclear Polarization by Thermal Mixing Under Partial Saturation

Jannin, S., A. Comment, and J. van der Klink, Dynamic Nuclear Polarization by Thermal Mixing Under Partial Saturation. Appl. Magn. Reson., 2012: p. 1-10.


We describe a low-temperature thermodynamic model for dynamic nuclear polarization (DNP) via continuous-wave partial saturation of electron spin resonance (ESR) lines that are both homogeneously and inhomogeneously broadened. It is a variant of a reasoning proposed by Borghini, which in turn used Redfield’s thermodynamic treatment of saturation. Our variant is furthermore based on Provotorov’s insight that under partial saturation of a coupled-spin system two distinct spin temperatures should appear in a thermodynamical theory. We apply our model to DNP results obtained at a temperature of 1.2 K and in magnetic fields of 3.35 and 5 T on 1- 13 C labeled sodium acetate dissolved in a frozen D 2 O/ethanol-d 6 solution doped with the free radical TEMPO.