High-Resolution NMR of Liquids and Gases: Effects of Magnetic-Field-Induced Molecular Alignment

This chapter presents a theoretical description of NMR of anisotropic systems. The special application of alignment in liquids and gases by the static magnetic field, used for high-resolution NMR spectroscopy is considered in the chapter. The chapter also considers the experimental aspects along with applications to diamagnetic and paramagnetic compounds. NMR spectra of the anisotropic liquid media are well-resolved due to the high mobilization of the solutes. An important role for the NMR method lies in linking it with other techniques such as the Cotton-Mouton effect, Kerr effect, electric-field NMR, and Rayleigh scattering. Determination of polarizabilities, hyperpolarizabilities, and local field factors in the other methods can be possible if NMR results are available to eliminate the unknowns in the working equations. The recent availability of accurate methods to determine small NMR line splittings as well as of the better resolution attainable on commercial spectrometers can greatly facilitate studies on small molecules.