Spin Relaxation in the High-field Limit

Abstract

This chapter presents high-field formalisms for spin–lattice relaxation, transverse relaxation under complete and incomplete motional-averaging conditions and the Overhauser effect. The treatments of transverse relaxation under incomplete motional averaging and the dipolar correlation variant are of the Anderson/Weiss type. The results are general for correlation functions and spectral densities to be defined application specifically. Reference is made to all types of spin couplings considered in Chapter 3. For didactic reasons, the descriptions of the formalisms are structured according to spin systems of increasing complexity. The spin ensembles considered are: (1) single spins 1/2 subject to fluctuating chemical shift anisotropy interactions; (2) single spins 1 subject to fluctuating quadrupole interactions; (3) systems of two spins coupled by fluctuating dipolar and scalar interactions; and (4) multispin systems potentially subject to all of the above interactions. In addition, the principles of the spin-temperature concept for spin–lattice relaxation and nuclear Overhauser effect spectroscopy (NOESY) are outlined.