The structural utility of three mechanisms of nuclear spin relaxation are considered. Examples illustrating the applicability of nuclear-nuclear dipolar relaxation in determining molecular microdynamics and solution geometry are presented. The use of spin-rotation relaxation to determine barriers to CH3 groups rotations and an example of quadrupole relaxation of deuteriums to probe molecular mo...

The interaction between the quadrupole moment of nuclear spins I > + with the electric-field-gradient (EFG) tensor leads to a splitting of the energy of the nuclear spin states. We show how the combination of laser and radio-frequency irradiation allows measurements of nuclear spin transitions in quadrupolar systems that are, in contrast to purely magnetic experiments, sensitive to the absolute...

Gate control of dynamic nuclear polarization under optical orientation is demonstrated in a Schottky-gated n-GaAs/AlGaAs (110) quantum well by time-resolved Kerr rotation measurements. Spin relaxation of electrons due to mechanisms other than the hyperfine interaction is effectively suppressed as the donor induced background electron density is reduced from metallic to insulating regimes. Subse...

We consider a protocol for the control of few-qubit registers comprising one electronic spin embedded in a nuclear spin bath. We show how to isolate a few proximal nuclear spins from the rest of the bath and use them as building blocks for a potentially scalable quantum information processor. We describe how coherent control techniques based on magnetic resonance methods can be adapted to these...

THEORY: The physics behind NMR/MRI signal production lies in the physics of spin. This section will cover enough aspects of spin to understand the generation of NMR signals. Although this initial spin discussion is inherently quantum mechanical in nature, we will later need to employ some simple principles from thermodynamics and classical dynamics to further describe the art of NMR. These topi...

When probing nuclear spins in materials on the nanometer scale, random fluctuations of the spin polarization will exceed the mean Boltzmann polarization for sample volumes below about (100 nm){3}. In this Letter, we use magnetic resonance force microscopy to observe nuclear spin fluctuations in real time. We show how reproducible measurements of the polarization variance can be obtained by cont...

In response to recent nuclear-magnetic-resonance (NMR) measurements on the molecular cluster Mn12O12 acetate, we study the nuclear spin-lattice relaxation rate 1/T(1), developing a modified spin-wave theory. Our microscopic new approach, which is distinct from previous macroscopic treatments of the cluster as a rigid spin of S=10, not only excellently interprets the observed temperature and app...

We present nuclear spin-rotation constants, absolute nuclear magnetic resonance (NMR) shielding constants, and shielding spans of all the nuclei in (175)LuX and (197)AuX (X = (19)F, (35)Cl, (79)Br, (127)I), calculated using coupled-cluster singles-and-doubles with a perturbative triples (CCSD(T)) correction theory, four-component relativistic density functional theory (relativistic DFT), and no...

Nuclear modulation in electron-spin-echo spectroscopy is conventionally studied by onedimensional electron-spin-echo envelope modulation ( lD-ESEEM) . Two-dimensional Fourier transform electron-spin resonance (2D-FTESR) studies of nuclear modulation have the promise of enhancing the spectral resolution and clarifying the key details of the relaxation processes. We present a 2D-FTESR study on si...

We discuss nuclear spin comagnetometers based on ultralow-field nuclear magnetic resonance in mixtures of miscible solvents, each rich in a different nuclear spin. In one version thereof, Larmor precession of protons and 19F nuclei in a mixture of thermally polarized pentane and hexafluorobenzene is monitored via a sensitive alkali-vapor magnetometer. We realize transverse relaxation times in e...