Polarity, signaling protocols

For these experiments, gated illumination for aperiod much shorter than the nuclear Ti was applied, and the polarizations were then sampled by an NMR pulse. This protocol results in a very good signal to noise ratio because the number of absorbed photons is large, and the CIDNP intensities are undisturbed by nuclear spin relaxation in the products. However, these experiments would also record the equilibrium NMR signals of unreacted molecules. This was avoided by special pulse sequences, and all spectra shown below are completely free from such background signals and represent pure polarizations only. 

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