Adiabatic transfer of net electron polarization to nuclear polarization

Abstract

A new type of spin chemical experiment is suggested which utilizes adiabatic reversion of a low magnetic B 0 field for an efficient transfer of net electron spin polarization, as arising from some CIDEP mechanism, to the nuclear polarization of radicals. After trapping the radicals in diamagnetic products and transferring the sample to a NMR probe, the adiabatic polarization transfer effect can be measured as induced CIDNP, as in the recently established SNP method. The optimum conditions concerning delay time and duration of the B 0 field switching, as well as the trapping rate constant are analysed quantitatively for a radical with one nuclear spin I = 1/2. Owing to their efficiency and some parameters that can be controlled in the experiment, adiabatic polarization transfer effects should have clear advantages over experiments relying on DNP effects due to the Overhauser mechanism.