Efficient Spectral Simulations in NMR of Rotating Solids. The γ-COMPUTE Algorithm

✍ Scribed by M. Hohwy; H. Bildsøe; H.J. Jakobsen; N.C. Nielsen

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 120 KB
• Volume: 136
• Category: Article
• ISSN: 1090-7807
• DOI: 10.1006/jmre.1998.1593

✦ Synopsis

We explore the time-translational relation between one of the powder angles (␥) and the sample rotation angle ( r t) in NMR spectroscopy of rotating solids. Averaging over the ␥ powder angle is shown to be generally equivalent to a cross correlation of two periodic functions. This leads to a fundamental relation concerning the phases of NMR spectra of rotating solids as well as improved strategies for efficient simulation of experimental spectra. Using these results in combination with the frequency-domain simulation procedure COMPUTE (M. Ede ´n et al., J. Magn. Reson. A 120, 56 (1996)), it proves possible to reduce the computation time for spectral simulations by typically a factor 10 -30 relative to the state-of-the-art calculations using the original COMPUTE algorithm. The advantage and the general applicability of the new simulation procedure, referred to as ␥-COMPUTE, are demonstrated by simulation of single-and multiple-pulse MAS NMR spectra of 31 P-31 P and 1 H-1 H spin pairs influenced by anisotropic chemical shielding and homonuclear dipolar interactions.