A Robust Algorithm for Isotropic Reconstruction of Magic-Angle Spinning Solid-State NMR Spectra
Abstract
Magic-angle spinning (MAS) is an essential component of most solid state NMR experiments. The use of finite spinning speeds results in spinning sidebands due to incomplete averaging of chemical shift anisotropy or quadrupole effects. Sidebands can seriously affect interpretation and quantitation, and the need to minimize them has had a pervasive influence on the practice of MAS NMR. We report a radically new approach for reconstructing spectra in the limit of infinite spinning speed from a set of experimental spectra obtained at various finite speeds. This is achieved using a robust algorithm that handles any number of sideband orders and deals with overlapping peaks. The full signal-to-noise advantage of acquiring multiple spectra is preserved in the reconstruction. Isotropic reconstruction is illustrated for C CP/MAS spectra for crystalline compounds and a representative polymer, P MAS spectra of a mixture, and 79Br MAS spectra of KBr. 19 orders of sidebands were used in the reconstruction of the latter example. A limitation of the present algorithm is that it requires spectra to be obtained at speeds sufficient to resolve the sidebands from the isotropic peaks. It thus fails to reconstruct the C CP/MAS spectrum of a coal from experimental spectra at very slow spinning speeds.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 23, 1992
- Accession Number
- ADA249610
Entities
People
- James F. Haw
- Nick C. Elbaum
Organizations
- Texas A&M University