Application of shaped adiabatic pulses to MQMAS NMR spectroscopy of spin 3/2 nuclei.
Competition between nutation (r.f. driven) and adiabatic (rotor-driven) multi-quantum coherence transfer mechanisms in spin 3/2 systems results in diminished performance of rotation induced adiabatic coherence transfer (RIACT) in isotropic multiple-quantum magic-angle spinning (MQMAS) experiments for small e(2)qQ/h (<2 MHz) and high radio-frequency powers. We present a simple shaped RIACT pulse consisting of a truncated sine wave (spanning 0-0.8pi) that corrects the sensitivity losses, phase twist and relative intensity errors that can arise in MQMAS spectra utilizing constant-amplitude RIACT pulses. The shaped RIACT pulse may enhance the study of metals in biomolecules where quadrupole couplings of S=3/2 nuclei such as (23)Na tend to be small.
Rovnyak
David
D
Bucknell University, Department of Chemistry, Moore Avenue, Lewisburg, PA 17837, USA. drovnyak@bucknell.edu
Kennedy
Paul E
PE
D004574:Electromagnetic Fields; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008280:Magnetics; D011789:Quantum Theory; D012964:Sodium / Q000737:chemistry*; D013057:Spectrum Analysis; D013113:Spin Labels; D041623:Tomography, Optical Coherence
D013113:Spin Labels; D012964:Sodium