title: Magnetic field gradients in solid state magic angle spinning NMR.
abstract: Magnetic field gradients have proven useful in NMR for coherence pathway selection, diffusion studies, and imaging. Recently they have been combined with magic angle spinning to permit high-resolution measurements of semi-solids, where magic angle spinning averages any residual dipolar couplings and local variations in the bulk magnetic susceptibility. Here we show the first examples of coherence pathway selection by gradients in dipolar coupled solids. When the gradient evolution competes with dipolar evolution the experiment design must take into account both the strength of the dipolar couplings and the means to refocus it. Examples of both homonuclear and heteronuclear experiments are shown in which gradients have been used to eliminate the need for phase cycling.
authors.affiliation: Bruker Instruments, Inc., 44 Manning Road, Billerica, Massachusetts 01821, USA.
authors.forename: W E
authors.initials: WE
authors.lastname: Maas
authors.forename: A
authors.initials: A
authors.lastname: Bielecki
authors.forename: M
authors.initials: M
authors.lastname: Ziliox
authors.forename: F H
authors.initials: FH
authors.lastname: Laukien
authors.forename: D G
authors.initials: DG
authors.lastname: Cory
mesh_terms: D005998:Glycine / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation*
chemical_list: D005998:Glycine