Chemically Induced Spin Hyperpolarization: Coherence Formation in Reaction Products

Abstract Chemically induced dynamic nuclear polarization (CIDNP) has emerged as a highly informative method to study spin-dependent radical reactions by analyzing enhanced NMR (nuclear magnetic resonance) signals of their diamagnetic reaction products. In this way, one can probe the structure elusive intermediates and determine parameters. A careful examination experimental CIDNP data at variable fields shows that formation hyperpolarized molecules in coherent state is ubiquitous though rarely discussed phenomenon. The presence spin coherences commonly leads subsequent transfer among coupled spins products recombination must be taken into account when results experiments low field. Moreover, such efficiently exploited polarize spins, which do not acquire directly. Here we explain under what conditions generated, focusing on key role level anti-crossings transfer, provide approaches probing time evolution. We illustrate theoretical consideration outlined phenomena examples, obtained for dipeptide tryptophan–tryptophan.