Basic Principles of NMR and Experimental Techniques

Abstract

This chapter introduces into NMR methods as the most important techniques for studying materials. The behaviour of spin system is considered in crossing magnetic fields from “classical” point of view. Basic equations for the vector of the bulk magnetisation M in outer magnetic field (Bloch equations) are discussed in rotating coordinate system. Spin-lattice (longitudinal) relaxation and spin-spin (transverse) relaxation are considered. The chapter describes the NMR experimental techniques for studying relaxation times T1, T2 and cross-relaxation. The role of proton exchange between the water and exchangeable protons of macromolecules is considered. Pulsed field gradient (PFG) NMR techniques are described for application in one- and twodimensions. Double-quantum-filtered (DQF) NMR spectroscopy is introduced as a technique to study the materials with anisotropic motion of molecules.

Keywords: Apparent diffusion coefficient Dapp, Double-quantum-filter (DQF) NMR, Fourier transform (FT), Free induction decay (FID), Inverse Laplace transformation (ILT), Nuclear Magnetic Resonance, Pulsed Field Gradient (PFG), Radio frequency (RF), Residual dipolar interaction (RDI), Spin-echo (SE), Spinlattice (longitudinal) relaxation time T1, Spin-spin (transverse) relaxation time T2, Stimulated echo (STE), Two-dimensional diffusion-diffusion correlation NMR spectroscopy (2D DDCOSY).