Several studies in experimental and theoretical magnetic resonance are presented. The longitudinal relaxation of solid $^{129}$Xe is shown to have an unexpected structural dependence from experiments that provide previously unattainable reproducibility; first-principles theories that attempt to describe the observed data are analyzed. Theoretical work is also presented that involves non-traditional methods of magnetic resonance detection, such as pulsed optically and electrically detected magnetic resonance (pODMR/pEDMR) of semiconducting material. This work confirms, using computational and theoretical methods, the presence of dipolar coupling between two paramagnetic spin-half states in a disordered semiconductor results in an increase of the pODMR/pEDMR Rabi frequency by a factor of $\sqrt{2}$; however, it is also shown there is strong exchange coupling between the pair. Additional Rabi oscillation studies are given that involve ordinary water NMR in the presence of a modulated longitudinal field, which confirm predictions of Rabi oscillation dynamics in three different regimes: fast-strong, slow-strong, and weak-resonant modulation.