Nuclear Spin Polarization from Triplet States in Solution

Abstract

AbstractProton and fluorine spin polarizations in solutions of optically excited p‐benzoquinones are shown to stem from the triplet states of the quinones. The phenomenon is analogous to the Optical Nuclear Polarization (ONP) effect in solids. ONP in solution is detected only if the relaxation processes among the triplet sublevels cannot destroy the polarization during the lifetimes of the triplets totally. The quinones are unique in having extremely short lived triplets. Therefore, ONP can be detected in their ground states by high resolution nmr, which allows to map out the electron distribution of the triplet states.