ABSTRACT
Most nuclear magnetic resonance work in solution is performed on spin 1/2 nuclei, exploiting their characteristic narrow lines. This chapter discusses spin systems containing such nuclei. It presents the basic properties of the interaction between the quadrupolar nuclei and the electric field gradients in a molecular system are introduced. For nuclear species with the spin quantum number of one or higher, the distribution of the electric charge within the nucleus is not spherically symmetric. This means that the electric energy of a nucleus depends on its orientation with respect to the inhomogeneous electric fields existing in a molecular framework. Transverse relaxation of quadrupolar nuclei can also be studied by employing radiofrequency fields in the form of either multiple-echo or spin-lock experiments. In a variety of interesting situations, monoatomic ions with quadrupolar nuclei can exchange between a bound site, where the ion is bound to a macromolecule, and a free site.
