| Summary: | <p>The solid-state effect of dynamic nuclear polarization (DNP) is operative also in viscous
liquids where the dipolar interaction between the electronic and nuclear spins is partially averaged.
The proper way to quantify the degree of averaging, and thus calculate the efficiency of the effect,
should be based on the time-correlation function of the dipolar interaction. Here we use
the stochastic Liouville equation formalism to develop a general theoretical description of the
solid effect in liquids. The derived expressions can be used with different dipolar correlations functions
depending on the assumed motional model. At high magnetic fields, the theory predicts DNP enhancements at small offsets, far from the classical solid-effect positions that are displaced by one nuclear Larmor
frequency from the electronic resonance. The predictions are in quantitative agreement with
such enhancement peaks observed at 9.4 T <span class="cit" id="xref_paren.1">(<a href="#bib1.bibx27">Kuzhelev et al.</a>, <a href="#bib1.bibx27">2022</a>)</span>. These non-canonical peaks are not due to thermal mixing or the cross effect but exactly follow the dispersive component of the EPR line.</p>
|
|---|