Residual dipolar couplings for pairs of proximate magnetic nuclei in macromolecules can easily be measured using high-resolution NMR methods when the molecules are dissolved in dilute liquid crystalline media. The resulting couplings can in principle be used to constrain the relative orientation of molecular fragments in macromolecular systems to build a complete structure. However, determinati...

Multi-spins tunneling cross-relaxations in an ensemble of weakly-coupled Ho 3+ ions, mediated by weak anisotropic dipolar interactions, can be ev-idenced by ac-susceptibility measurements in a high temperature regime. Based on a four-body representation, including the rare-earth nuclear spin, two-ions tunneling mechanisms can be attributed to both dipolar-biased tun-neling and co-tunneling proc...

The 1(01)-0(00), 2(02)-1(01), and 3(03)-2(02) rotational transitions of the FCO radical are observed at 22.3, 44.5, and 66.8 GHz, respectively, using a Fourier transform millimeter-wave spectrometer with a pulsed discharge nozzle. The FCO radical is produced by discharging F(2)CO diluted in the Ar buffer gas. Twelve fine and hyperfine components for the three transitions are observed, and the e...

Recently, the ordering of pyrochlore magnets consisting of corner-sharing network of tetrahedra has attracted much attention due to an intrinsic effect of geometrical frustration. Intensive studies were performed in particular on “spin-ice” magnets, e.g., Ho2Ti2O7 and Dy2Ti2O7, which possesses a strong Ising-like < 111 > magnetic anisotropy and exhibits an intriguing glassy behavior analogous t...

The global fold of maltose-binding protein in complex with the substrate beta-cyclodextrin was determined by solution NMR methods. The two-domain protein is comprised of a single polypeptide chain of 370 residues, with a molecular mass of 42 kDa. Distance information in the form of H(N)-H(N), H(N)-CH(3) and CH(3)-CH(3) NOEs was recorded on (15)N, (2)H and (15)N, (13)C, (2)H-labeled proteins wit...

Molecular conformation is important in chemistry and biochemistry. Conformers connected by low energy barriers can only be observed at low temperatures and are difficult to be separated. Here we report a new method to obtain conformation-selective spectroscopic information about dipolar molecular radicals via dipole-bound excited states of the corresponding anions cooled in a cryogenic ion trap...

A strong magnetic field can make it advantageous to work in a coordinate system aligned with dipolar field lines. This monograph collect the formulas for some of the most frequently used expressions and operations in dipole coordinates. In some physical systems (e.g., the terrestrial ionosphere or the solar corona) the magnetic field can impose a strong anisotropy by restricting transport proce...

The orientation data provided by solid-state NMR can provide a great deal of structural information about membrane proteins. The quality of the information provided is, however, somewhat degraded by sign degeneracies in measurements of the dipolar coupling tensor. This is reflected in the dipolar coupling penalty function used in atomic refinement, which is less capable of properly restraining ...