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Cross polarization under fast magic angle spinning: thermodynamical considerations

✍ Scribed by B.H. Meier

Publisher: Elsevier Science
Year: 1992
Tongue: English
Weight: 554 KB
Volume: 188
Category: Article
ISSN: 0009-2614
DOI: 10.1016/0009-2614(92)90009-c

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✦ Synopsis

Thermodynamic aspects of cross polarization under fast magic angle sample spinning are studied. An extension of the static cross-polarization model is presented which applies to the "sidebands" ofthe Hartmann-Hahn condition. The cross-polarization process for the "sidebands" is not spin-energy conserving but energy is supplied or adsorbed by the sample rotation. For a static sample, cross polarization proceeds through heteronuclear zero-quantum transitions. For a rotating sample, zero-quantum as well as doublequantum cross polarization is observed experimentally. This behavior is explained by the extended model.

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