Abstract
Spectral lineshapes of MAS NMR spectra of dipolar (re)coupled spin pairs exhibiting considerable chemical shielding anisotropies at and near the so-called n = 0 rotational resonance (R-2) condition are considered. The n = 0 R-2 condition is found to be not extremely sharp. Anisotropic interaction parameters such as chemical shielding tensor orientations and the magnitude of the dipolar coupling constant remain sensitively encoded in such lineshapes even when differences in isotropic chemical shielding values of up to 400 Hz (corresponding to ca. half the size of the dipolar coupling constant) are present. Additional double-quantum filtration (DQF) may enhance the sensitivity of spectral lineshapes to anisotropic interaction parameters for even larger differences in isotropic chemical shielding values. The dependence of the DQF efficiency on spin-system parameters as well as on external parameters (Larmor and MAS frequencies) is investigated. Away from R-2 conditions a trend to lower DQF efficiencies is found whereas some spin-system parameters are more sensitively encoded in the corresponding spectral lineshapes. Our study is based on numerical simulations, with the known parameters of the P-31 spin pair in Na(4)P(2)O(7)(.)10H(2)O representing our model case. (c) 2005 Elsevier Inc. All rights reserved.
| Original language | English |
|---|---|
| Pages (from-to) | 296-304 |
| Number of pages | 9 |
| Journal | Journal of Magnetic Resonance |
| Volume | 173 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - Apr 2005 |
Keywords
- MAS NMR
- rotational resonance
- double-quantum filtration
- numerical simulations
- NUCLEAR-MAGNETIC-RESONANCE
- SOLID-STATE NMR
- CHEMICAL SHIELDING ANISOTROPIES
- HOMONUCLEAR 2-SPIN SYSTEMS
- ANGLE-SPINNING NMR
- FLOQUET THEORY
- INTERNUCLEAR DISTANCES
- DIPOLAR
- SIMULATIONS
- ORIENTATIONS
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