Theoretical and experimental studies of chemically induced electron-nuclear polarization in low magnetic fields

Abstract

Chemically induced electron-nuclear polarization at low magnetic fields is considered theoretically for a radical with one magnetic nucleus. It is shown that large non-equilibrium populations of the radical spin levels are expected to exist under low magnetic fields. This large electron-nuclear polarization has been observed experimentally during the photolysis of two phosphine oxides using a modified L-band TREPR setup. The TREPR spectra and kinetics of dimethoxyphosphonyl and diphenylphosphonyl radicals have been measured and analysed in low magnetic fields, and excellent agreement between experiment and theory has been achieved.