High Resolution NMR in Solids: Selective Averaging

anisotropy applied field atoms axes axially symmetric axis B₁ CaF2 Chem chemical shifts coefficients correction terms cos² cross terms decay decoupling density matrix dependence effects Euler angles experimental ferrocene flip angle errors frequency H bond H₂ Haeberlen high-resolution NMR hydrogen bonds I-spin interactions internal Hamiltonians isotropic J. S. Waugh linewidth magic-angle magnetic field maleic acid malonic acid molecular molecular symmetry molecules motions MREV sequence multiple-pulse sequences NMR in solids NMR signal nuclear spin nuclei off-resonance averaging orientation parameters perpendicular phase transients Phys plane proton proton shielding pulse imperfections pulse sequence resolution rf field rf inhomogeneity rotating frame sample spinning secular self-decoupling shielded direction shielding tensors sin² single crystal spectrum spin space spin system spin-spin spin-spin coupling subcycle T₁ toggling frame tonian tw/t vanishes w₁ WAHUHA cycle WAHUHA experiment WAHUHA sequence wref Δω