MLEV-17-based two-dimensional homonuclear magnetization transfer spectroscopy

An Improved Broadband Decoupling Sequence for Liquid Crystals and Solids

Computer-optimized decoupling scheme for wideband applications and low-level operation

Fifty years of developments in nuclear magnetic resonance (NMR) have resulted in an unrivaled degree of control of the dynamics of coupled two-level quantum systems. This coherent control of nuclear spin dynamics has recently been taken to a new level, motivated by the interest in quantum information processing. NMR has been the workhorse for the experimental implementation of quantum protocols, allowing exquisite control of systems up to seven qubits in size. This article surveys and summarizes a broad variety of pulse control and tomographic techniques which have been developed for, and used in, NMR quantum computation. Many of these will be useful in other quantum systems now being considered for the implementation of quantum information processing tasks.

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NMR techniques for quantum control and computation

Ionic liquid crystals.

Fluorine-19 relaxation study of perfluoro chemicals as oxygen carriers

A method called RHODIUM (removal of homonuclear dipolar coupling and the use of off‐magic‐angle spinning) can be applied effectively to study the carbon‐13 NMR of liquid crystals in natural abundance. In this method, the sample is spun rapidly (∼1 kHz) at an angle (θ) slightly less than the magic angle, so that the nematic director aligns along the spinning axis and the dipolar couplings are reduced by a factor of (3 cos2 θ−1)/2. Proton–proton dipolar couplings are removed by a special decoupling sequence (BLEW‐48) so that carbon–proton dipolar couplings can be readily identified. The coupling constants (DC–H) of individual carbons are obtained by using a two‐dimensional technique of separated local field spectroscopy. The RHODIUM method has been used to study the molecular ordering in the nematic phase of 4‐n‐alkyl‐4’‐cyanobiphenyls (kCB). Three homologs (5CB, 6CB, and 7CB) were investigated at TNI−T =4 K. Values of DC–H of the aliphatic carbons give rich information on the energetics of chain conformati...

Nematic ordering of 4‐n‐alkyl‐4’‐cyanobiphenyls studied by carbon‐13 NMR with off‐magic‐angle spinning

Three new homologous series of mesogens containing three rings in the main structure and a lateral aromatic branch have been synthesized. When the lateral aromatic branch is attached to the middle ring, monotropic phases are observed, and there is a strong tendency to form the smectic C phase. When the lateral aromatic branch is attached to an outer ring, the compounds possess purely enantiotropic nematic phases. The terminal alkoxy chain in the outer ring which has a lateral aromatic substituent can be replaced by a rigid group without disturbing the large nematic range. Selective introduction of a particular substitutent may be useful for the construction of devices possessing desirable characteristics such as non-linear optical properties.

B. M. Fung

Papers

An Improved Broadband Decoupling Sequence for Liquid Crystals and Solids

Fluorine-19 relaxation study of perfluoro chemicals as oxygen carriers

Nematic ordering of 4‐n‐alkyl‐4’‐cyanobiphenyls studied by carbon‐13 NMR with off‐magic‐angle spinning

New laterally aromatic branched liquid crystal materials with large nematic ranges

Carbon-13 NMR of liquid crystals. Spinning near the magic angle with proton-proton dipolar decoupling