Spectrometer for heteronuclear magnetic double resonance

A spectrometer system suitable for heteronuclear magnetic double resonance studies is described which is based on a permanent magnet providing a field at 9400 G and on a detection system employing a radio-frequency bridge. The system permits the observation of magnetic resonance signals of protons decoupled from a variety of other nuclei, e.g. 14N, 31P, 75As, and hence the measurement of the chemical shifts of these nuclei. Selective decouplings leading to the determination of relative signs of coupling constants are possible. In the case of 15N effects specific to 0.1 c/s in the 15N resonance frequency have been found, and line positions in the 15N region have been measured.