Dynamic Polarisation of Nuclei by Saturation of Forbidden Transitions

Abstract

The degree of dynamic nuclear polarisation in a multi-level electron-nuclear coupled spin system is computed in the high temperature limit when the first order forbidden transitions are saturated by an appropriate microwave field. Both the cases of either the hyperfine or the nuclear Zeeman interaction dominating over the other are discussed. In the latter case the enhancement of nuclear magnetic resonance is also calculated and compared with the available experimental data.