Dynamic polarization of protons and fluorine nuclei in solutions of free radicals

Abstract

Further measurements of the nuclear electron Overhauser effect in solutions are reported for fluorine and protons. The proton-electron interaction is predominantly dipolar and the results are satisfactorily interpreted in terms of a model of randomly diffusing spheres. Fluorine-electron interactions, however, involve a scalar contribution, and current theories for the time dependence of this interaction give qualitative but not quantitative agreement with experiment. The effect of stimulated emission on the observed enhancements is discussed and concluded to be small in these experiments.