Molecular crystals and liquid crystals · 1985 · 13 citations · 5 references
Natural SciencesChemistryPhysicsCondensed Matter PhysicsSolid-state ChemistrySpectroscopyCrystal ChemistryLiquid CrystalsMagnetic Properties Of SolidsMagnetic Resonance SpectroscopyPhase TransitionsSolid-state Phase TransitionsCarbon-13 Nuclear Magnetic ResonanceMagnetic Resonance Relaxation TimesNuclear Magnetic Resonance RelaxationRelaxation Time MeasurementsRelaxation TimesSmectic Liquid CrystalsSmectic PhasesSpin-lattice Relaxation
Abstract The l3C chemical shifts and spin-lattice relaxation times were obtained for all the resolved resonances in the isotropic, nematic, and smectic phases of 8CB. NOE measurements were also obtained for the isotropic phase. A study of these data reveal some inconsistencies with dielectric and deuterium NMR studies, but general agreement with a 13C NMR study of 5CB. Discontinuities in relaxation times at both the nematic/isotropic and smectic/nematic phase transitions are observed for some of the carbon atoms. The difference between the components of the motionally averaged shielding tensor parallel and perpendicular to the long molecular axis is found for both the aromatic carbons and the first carbon of the octyl chain.
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