The Effect of RF Inhomogeneity on Heteronuclear Dipolar Recoupling in Solid State NMR: Practical Performance of SFAM and REDOR
✍ Scribed by Katsuyuki Nishimura; Riqiang Fu; Timothy A. Cross
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 161 KB
- Volume
- 152
- Category
- Article
- ISSN
- 1090-7807
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✦ Synopsis
Practical heteronuclear dipolar recoupling performances under magic angle spinning for SFAM and REDOR have been investigated under well-defined rf inhomogeneity environments with variation of resonance offsets for the irradiated nucleus. The heteronuclear dipolar recoupling efficiencies were quantitatively determined based on the experimentally obtained rf homogeneity. As a result, SFAM retains higher recoupling efficiency (>95%) at an 85% effective nutation frequency, and its recoupling efficiency is gradually reduced at lower effective nutation frequencies. On the other hand, although REDOR retains higher recoupling (>95%) efficiency at high (>92%) effective nutation frequency with an XY-8 compensation pulse sequence, the recoupling efficiency is dramatically decreased when the effective nutation frequency is below 90%. Over all, SFAM has significant advantages for insensitivity to carrier frequency offset and rf inhomogeneity.