Powder MAS NMR lineshapes of quadrupolar nuclei in the presence of second-order quadrupole interaction.
Solid State Nucl Magn Reson
; 16(4): 305-38, 2000 Jul.
Article
em En
| MEDLINE
| ID: mdl-10928635
ABSTRACT
We derive a complete analytical solution for the powder magic angle spinning (MAS) nuclear magnetic resonance (NMR) lineshape in the presence of second-order quadrupole interaction, considering a radiofrequency (rf) pulse of finite width, a finite MAS frequency, and a non-zero asymmetry parameter. (Ix) is calculated using two approaches. The first applies time-dependent perturbation theory in the presence of the rf pulse and stationary perturbation theory (SPT) in its absence. The second is based on the Magnus expansion of the density matrix in the interaction representation during the pulse and SPT in its absence. We solve the problem in the laboratory frame using the properties of the Fourier transform and spin operators. Diagonalisation is not required. Both approaches agree well with each other under all conditions and also with the transition probability approach for the central transition. The Magnus expansion exists at all times and the effect of the non-secular terms is negligible. We describe an analytical method of averaging (Ix) over the Euler angles and simulate the 11B MAS NMR lineshapes for crystalline and vitreous B2O3. A critical analysis is given of all earlier calculations of the MAS NMR lineshape.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Espectroscopia de Ressonância Magnética
Idioma:
En
Revista:
Solid State Nucl Magn Reson
Assunto da revista:
DIAGNOSTICO POR IMAGEM
/
MEDICINA NUCLEAR
Ano de publicação:
2000
Tipo de documento:
Article