Rotational Resonance in the Nuclear Magnetic Resonance of solids

Abstract: This thesis presents new physical phenomena in the rotational resonance NMR of magic-angle spinning solids. The theory of a new class of nuclear spin echoes is developed. These spin echoes, excited by rotational resonance, demonstrate the general physical principle that time dependent dynamics may in some circumstances be reversed by external intervention. Rotational resonance echoes reveal specific properties of the relaxation behaviour of coupled spin-1/2 nuclei.New methods for efficient excitation of multiple-quantum coherence by rotational resonance echoes, are presented. These experiments are extended to also work with high efficiency at spinning frequencies not satisfying a rotational resonance condition. The above methods employ modest radio-frequency irradiation of the recoupled spin species and are feasible at high magic-angle spinning frequencies. These experiments are important as central building blocks in the development of methods for structure determination, such as the determination of internuclear distances and molecular torsion angles.