Chemical shift anisotropy amplification

A new NMR experiment which allows a measurement of the chemical shift anisotropy (CSA) tensor under magic angle spinning (MAS) is described. This correlates a fast MAS spectrum in the omega(2) dimension with a sideband pattern in omega(1) in which the intensities mimic those for a sample spinning at a fraction of the rate omega(r)/N, and these sidebands result from an amplification by a factor N of the modulation caused by the CSA. Standard methods can be used to extract the principal tensor components from the omega(1) sideband patterns, and the nature of the experiment is such that the use of a large number of t(1) increments can avoided without compromising the resolution of different chemical sites. The new experiment is useful for accurately measuring narrow shift anisotropies. (C) 2003 Elsevier Inc. All rights reserved.