Multiple-quantum cross polarization in quadrupolar spin systems during magic-angle spinning.
We describe the concept of multiple-quantum cross polarization (CP) between an I = 32 and an I = 12 spin during magic-angle spinning. Experimental and theoretical results for (23)Na-(1)H pairs are presented that elucidate the transfer mechanism and the beneficial effect of adiabatic amplitude modulations of the CP field. The multiple-quantum CP approach is shown to be beneficial for improving the sensitivity of CP-MQMAS experiments and for detecting dipolar correlations.
Rovnyak
D
D
Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Baldus
M
M
Griffin
R G
RG
D009682:Magnetic Resonance Spectroscopy / Q000379:methods*