Packet-Shifting Electron-Nuclear Double-Resonance Mechanisms

Mechanisms of electron-nuclear double resonance (ENDOR) which involve the shift of spin packets are discussed in relation to experiments performed on phosphorus-doped silicon and irradiated frozen sulfuric acid. Both homogeneously saturated and inhomogeneously saturated electron-paramagnetic-resonance (EPR) transitions are considered. In the case of homogeneous packet-shifting ENDOR, the presence or absence of certain relaxation paths determines the sign and size of the ENDOR response. In the case of inhomogeneous packet-shifting ENDOR, the saturation and passage conditions also determine the nature of the ENDOR response.